How to use the wagtail.core.fields function in wagtail

field=wagtail.core.fields.RichTextField(blank=True, null=True),
        ),
        migrations.AddField(
            model_name="articlepage",
            name="featured_image",
            field=models.ForeignKey(
                blank=True,
                null=True,
                on_delete=django.db.models.deletion.PROTECT,
                to="core.CustomImage",
            ),
        ),
        migrations.AlterField(
            model_name="articlepage",
            name="body",
            field=wagtail.core.fields.StreamField(
                [
                    ("paragraph", wagtail.core.blocks.RichTextBlock()),
                    (
                        "photo",
                        wagtail.core.blocks.StructBlock(
                            [
                                ("image", wagtail.images.blocks.ImageChooserBlock()),
                                (
                                    "caption",
                                    wagtail.core.blocks.RichTextBlock(
                                        features=["bold", "italic"], required=False
                                    ),
                                ),
                                (
                                    "size",
                                    wagtail.core.blocks.ChoiceBlock(

class Migration(migrations.Migration):

    initial = True

    dependencies = [
        ('wagtailcore', '0040_page_draft_title'),
        ('wagtailimages', '0021_image_file_hash'),
    ]

    operations = [
        migrations.CreateModel(
            name='GalleryIndex',
            fields=[
                ('page_ptr', models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, serialize=False, to='wagtailcore.Page')),
                ('intro', wagtail.core.fields.RichTextField(blank=True, help_text='Optional text to go with the intro text.', verbose_name='Intro text')),
                ('images_per_page', models.IntegerField(default=10, help_text='How many images there should be on one page.', verbose_name='Images per page')),
                ('order_images_by', models.IntegerField(choices=[(1, 'Image title'), (2, 'Newest image first')], default=1)),
                ('collection', models.ForeignKey(help_text='Show images in this collection in the gallery view.', null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to='wagtailcore.Collection', verbose_name='Collection')),
                ('feed_image', models.ForeignKey(blank=True, help_text='An optional image to represent the page', null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to='wagtailimages.Image')),
            ],
            options={
                'verbose_name': 'Photo Gallery',
                'verbose_name_plural': 'Photo Galleries',
            },
            bases=('wagtailcore.page',),
        ),

from django.db import migrations
import wagtail.core.blocks
import wagtail.core.fields
import wagtail.images.blocks


class Migration(migrations.Migration):

    dependencies = [("topics", "0021_auto_20190701_1105")]

    operations = [
        migrations.AlterField(
            model_name="topic",
            name="get_started",
            field=wagtail.core.fields.StreamField(
                [
                    (
                        "panel",
                        wagtail.core.blocks.StructBlock(
                            [
                                ("title", wagtail.core.blocks.CharBlock()),
                                ("image", wagtail.images.blocks.ImageChooserBlock()),
                                ("description", wagtail.core.blocks.TextBlock()),
                                ("button_text", wagtail.core.blocks.CharBlock()),
                                (
                                    "button_destination",
                                    wagtail.core.blocks.PageChooserBlock(),
                                ),

primary_key=True,
                        serialize=False,
                        to="wagtailcore.Page",
                    ),
                )
            ],
            options={"abstract": False},
            bases=("wagtailcore.page",),
        ),
        migrations.AlterModelOptions(
            name="event", options={"ordering": ["-start_date"]}
        ),
        migrations.AddField(
            model_name="event",
            name="agenda",
            field=wagtail.core.fields.StreamField(
                [
                    (
                        "agenda_item",
                        wagtail.core.blocks.StructBlock(
                            [
                                ("start_time", wagtail.core.blocks.TimeBlock()),
                                (
                                    "end_time",
                                    wagtail.core.blocks.TimeBlock(required=False),
                                ),
                                ("title", wagtail.core.blocks.CharBlock()),
                                (
                                    "speaker",
                                    wagtail.core.blocks.PageChooserBlock(
                                        page_type=["people.Person"], required=False
                                    ),

field=models.CharField(verbose_name='Header Title', max_length=255, blank=True),
        ),
        migrations.AlterField(
            model_name='homepage',
            name='title_sl',
            field=models.CharField(verbose_name='Header Title', max_length=255, blank=True),
        ),
        migrations.AlterField(
            model_name='homepage',
            name='title_sv',
            field=models.CharField(verbose_name='Header Title', max_length=255, blank=True),
        ),
        migrations.AlterField(
            model_name='simplepage',
            name='body_da',
            field=wagtail.core.fields.StreamField((('heading', wagtail.core.blocks.CharBlock(icon='title', classname='full title')), ('paragraph', wagtail.core.blocks.TextBlock(icon='pilcrow')), ('rich_text', wagtail.core.blocks.RichTextBlock(icon='pilcrow')), ('image', wagtail.images.blocks.ImageChooserBlock(icon='image')), ('wide_image', wagtail.core.blocks.StructBlock((('image', wagtail.images.blocks.ImageChooserBlock()),), icon='image')), ('images', wagtail.core.blocks.StructBlock((('left_image', wagtail.images.blocks.ImageChooserBlock()), ('left_image_text', wagtail.core.blocks.TextBlock()), ('middle_image', wagtail.images.blocks.ImageChooserBlock()), ('middle_image_text', wagtail.core.blocks.TextBlock()), ('right_image', wagtail.images.blocks.ImageChooserBlock()), ('right_image_text', wagtail.core.blocks.TextBlock()), ('circles', wagtail.core.blocks.BooleanBlock())), icon='image')), ('contact_block', wagtail.core.blocks.StructBlock((('title', wagtail.core.blocks.CharBlock(classname='full title')), ('name_label', wagtail.core.blocks.CharBlock(classname='full title')), ('email_label', wagtail.core.blocks.CharBlock(classname='full title')), ('subject_label', wagtail.core.blocks.CharBlock(classname='full title')), ('message_label', wagtail.core.blocks.CharBlock(classname='full title')), ('submit_label', wagtail.core.blocks.CharBlock(classname='full title'))), icon='form')), ('accordion_block', wagtail.core.blocks.StructBlock((('accordion_items', wagtail.core.blocks.ListBlock(wagtail.core.blocks.StructBlock((('title', wagtail.core.blocks.TextBlock(required=False)), ('content', wagtail.core.blocks.TextBlock(required=False)))))),), icon='collapse-down'))), verbose_name='body', blank=True, null=True),
        ),
        migrations.AlterField(
            model_name='simplepage',
            name='body_de',
            field=wagtail.core.fields.StreamField((('heading', wagtail.core.blocks.CharBlock(icon='title', classname='full title')), ('paragraph', wagtail.core.blocks.TextBlock(icon='pilcrow')), ('rich_text', wagtail.core.blocks.RichTextBlock(icon='pilcrow')), ('image', wagtail.images.blocks.ImageChooserBlock(icon='image')), ('wide_image', wagtail.core.blocks.StructBlock((('image', wagtail.images.blocks.ImageChooserBlock()),), icon='image')), ('images', wagtail.core.blocks.StructBlock((('left_image', wagtail.images.blocks.ImageChooserBlock()), ('left_image_text', wagtail.core.blocks.TextBlock()), ('middle_image', wagtail.images.blocks.ImageChooserBlock()), ('middle_image_text', wagtail.core.blocks.TextBlock()), ('right_image', wagtail.images.blocks.ImageChooserBlock()), ('right_image_text', wagtail.core.blocks.TextBlock()), ('circles', wagtail.core.blocks.BooleanBlock())), icon='image')), ('contact_block', wagtail.core.blocks.StructBlock((('title', wagtail.core.blocks.CharBlock(classname='full title')), ('name_label', wagtail.core.blocks.CharBlock(classname='full title')), ('email_label', wagtail.core.blocks.CharBlock(classname='full title')), ('subject_label', wagtail.core.blocks.CharBlock(classname='full title')), ('message_label', wagtail.core.blocks.CharBlock(classname='full title')), ('submit_label', wagtail.core.blocks.CharBlock(classname='full title'))), icon='form')), ('accordion_block', wagtail.core.blocks.StructBlock((('accordion_items', wagtail.core.blocks.ListBlock(wagtail.core.blocks.StructBlock((('title', wagtail.core.blocks.TextBlock(required=False)), ('content', wagtail.core.blocks.TextBlock(required=False)))))),), icon='collapse-down'))), verbose_name='body', blank=True, null=True),
        ),
        migrations.AlterField(
            model_name='simplepage',
            name='body_en',
            field=wagtail.core.fields.StreamField((('heading', wagtail.core.blocks.CharBlock(icon='title', classname='full title')), ('paragraph', wagtail.core.blocks.TextBlock(icon='pilcrow')), ('rich_text', wagtail.core.blocks.RichTextBlock(icon='pilcrow')), ('image', wagtail.images.blocks.ImageChooserBlock(icon='image')), ('wide_image', wagtail.core.blocks.StructBlock((('image', wagtail.images.blocks.ImageChooserBlock()),), icon='image')), ('images', wagtail.core.blocks.StructBlock((('left_image', wagtail.images.blocks.ImageChooserBlock()), ('left_image_text', wagtail.core.blocks.TextBlock()), ('middle_image', wagtail.images.blocks.ImageChooserBlock()), ('middle_image_text', wagtail.core.blocks.TextBlock()), ('right_image', wagtail.images.blocks.ImageChooserBlock()), ('right_image_text', wagtail.core.blocks.TextBlock()), ('circles', wagtail.core.blocks.BooleanBlock())), icon='image')), ('contact_block', wagtail.core.blocks.StructBlock((('title', wagtail.core.blocks.CharBlock(classname='full title')), ('name_label', wagtail.core.blocks.CharBlock(classname='full title')), ('email_label', wagtail.core.blocks.CharBlock(classname='full title')), ('subject_label', wagtail.core.blocks.CharBlock(classname='full title')), ('message_label', wagtail.core.blocks.CharBlock(classname='full title')), ('submit_label', wagtail.core.blocks.CharBlock(classname='full title'))), icon='form')), ('accordion_block', wagtail.core.blocks.StructBlock((('accordion_items', wagtail.core.blocks.ListBlock(wagtail.core.blocks.StructBlock((('title', wagtail.core.blocks.TextBlock(required=False)), ('content', wagtail.core.blocks.TextBlock(required=False)))))),), icon='collapse-down'))), verbose_name='body', blank=True, null=True),
        ),
        migrations.AlterField(
            model_name='simplepage',
            name='body_fr',
            field=wagtail.core.fields.StreamField((('heading', wagtail.core.blocks.CharBlock(icon='title', classname='full title')), ('paragraph', wagtail.core.blocks.TextBlock(icon='pilcrow')), ('rich_text', wagtail.core.blocks.RichTextBlock(icon='pilcrow')), ('image', wagtail.images.blocks.ImageChooserBlock(icon='image')), ('wide_image', wagtail.core.blocks.StructBlock((('image', wagtail.images.blocks.ImageChooserBlock()),), icon='image')), ('images', wagtail.core.blocks.StructBlock((('left_image', wagtail.images.blocks.ImageChooserBlock()), ('left_image_text', wagtail.core.blocks.TextBlock()), ('middle_image', wagtail.images.blocks.ImageChooserBlock()), ('middle_image_text', wagtail.core.blocks.TextBlock()), ('right_image', wagtail.images.blocks.ImageChooserBlock()), ('right_image_text', wagtail.core.blocks.TextBlock()), ('circles', wagtail.core.blocks.BooleanBlock())), icon='image')), ('contact_block', wagtail.core.blocks.StructBlock((('title', wagtail.core.blocks.CharBlock(classname='full title')), ('name_label', wagtail.core.blocks.CharBlock(classname='full title')), ('email_label', wagtail.core.blocks.CharBlock(classname='full title')), ('subject_label', wagtail.core.blocks.CharBlock(classname='full title')), ('message_label', wagtail.core.blocks.CharBlock(classname='full title')), ('submit_label', wagtail.core.blocks.CharBlock(classname='full title'))), icon='form')), ('accordion_block', wagtail.core.blocks.StructBlock((('accordion_items', wagtail.core.blocks.ListBlock(wagtail.core.blocks.StructBlock((('title', wagtail.core.blocks.TextBlock(required=False)), ('content', wagtail.core.blocks.TextBlock(required=False)))))),), icon='collapse-down'))), verbose_name='body', blank=True, null=True),
        ),

from django.db import migrations
import wagtail.core.blocks
import wagtail.core.fields
import wagtail.images.blocks


class Migration(migrations.Migration):

    dependencies = [("people", "0021_auto_20190731_1057")]

    operations = [
        migrations.AddField(
            model_name="person",
            name="websites",
            field=wagtail.core.fields.StreamField(
                [
                    (
                        "website",
                        wagtail.core.blocks.StructBlock(
                            [
                                ("url", wagtail.core.blocks.URLBlock(label="URL")),
                                (
                                    "title",
                                    wagtail.core.blocks.CharBlock(required=False),
                                ),
                                (
                                    "icon",
                                    wagtail.images.blocks.ImageChooserBlock(
                                        required=False
                                    ),
                                ),

fields=[
                ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
                ('name', models.CharField(max_length=255)),
                ('link', models.CharField(max_length=1024)),
            ],
            options={
                'abstract': False,
            },
        ),
        migrations.CreateModel(
            name='TextBlock',
            fields=[
                ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
                ('name', models.CharField(max_length=255)),
                ('heading', models.TextField(default='', blank=True)),
                ('content', wagtail.core.fields.RichTextField(default='', blank=True)),
            ],
            options={
                'abstract': False,
            },
        ),
        migrations.CreateModel(
            name='LogoBlock',
            fields=[
                ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
                ('name', models.CharField(max_length=255)),
                ('logo', models.ForeignKey(to='images.AttributedImage', on_delete=models.deletion.CASCADE)),
            ],
            options={
                'abstract': False,
            },
        ),

from django.db import migrations
import wagtail.core.blocks
import wagtail.core.fields
import wagtail.images.blocks


class Migration(migrations.Migration):

    dependencies = [("events", "0015_auto_20190813_1503")]

    operations = [
        migrations.AlterField(
            model_name="event",
            name="speakers",
            field=wagtail.core.fields.StreamField(
                [
                    (
                        "speaker",
                        wagtail.core.blocks.PageChooserBlock(
                            page_type=["people.Person"]
                        ),
                    ),
                    (
                        "external_speaker",
                        wagtail.core.blocks.StructBlock(
                            [
                                ("title", wagtail.core.blocks.CharBlock(label="Name")),
                                ("job_title", wagtail.core.blocks.CharBlock()),
                                ("image", wagtail.images.blocks.ImageChooserBlock()),
                                (
                                    "url",

from django.db import migrations
import wagtail.core.blocks
import wagtail.core.fields
import wagtail.images.blocks


class Migration(migrations.Migration):

    dependencies = [("topics", "0035_auto_20190725_1225")]

    operations = [
        migrations.AlterField(
            model_name="topic",
            name="featured",
            field=wagtail.core.fields.StreamField(
                [
                    (
                        "article",
                        wagtail.core.blocks.PageChooserBlock(
                            page_type=[
                                "articles.Article",
                                "externalcontent.ExternalArticle",
                            ],
                            required=False,
                        ),
                    ),
                    (
                        "external_page",
                        wagtail.core.blocks.StructBlock(
                            [
                                ("url", wagtail.core.blocks.URLBlock()),