How to use the tern.formats.spdx.formats function in tern

def get_document_namespace(image_obj):
    '''Given the image object, return a unique SPDX document uri.
    This is a combination of the human readable id from the image
    object and the tool name'''
    return spdx_formats.document_namespace.format(
        image_id=image_obj.get_human_readable_id(),
        version=get_git_rev_or_version()[1])

def get_package_comment(origins):
    '''Return a PackageComment tag-value text block for a list of
    NoticeOrigin objects'''
    comment = ''
    if origins:
        for notice_origin in origins:
            comment = comment + content.print_notices(
                notice_origin, '', '\t')
        return spdx_formats.package_comment.format(comment=comment)
    return comment

def get_document_block(image_obj):
    '''Return document related SPDX tag-values'''
    block = spdx_formats.spdx_version + '\n'
    block = block + spdx_formats.data_license + '\n'
    block = block + spdx_formats.spdx_id + '\n'
    block = block + spdx_formats.document_name.format(
        image_name=image_obj.get_human_readable_id()) + '\n'
    block = block + get_document_namespace(image_obj) + '\n'
    block = block + spdx_formats.license_list_version + '\n'
    block = block + spdx_formats.creator.format(
        version=get_git_rev_or_version()[1]) + '\n'
    block = block + spdx_formats.created.format(
        timestamp=datetime.datetime.utcnow().strftime(
            "%Y-%m-%dT%H:%M:%SZ")) + '\n'
    block = block + spdx_formats.document_comment + '\n'
    return block

def get_layer_relationships(layer_obj, prev_layer_spdxref=None):
    '''Given the layer object, return the relationships of the layer
    objects to packages and to the previous layer'''
    block = ''
    layer_reference = get_layer_spdxref(layer_obj)
    if prev_layer_spdxref:
        block = block + spdx_formats.prereq.format(
            after=layer_reference, before=prev_layer_spdxref) + '\n'
    for package in layer_obj.packages:
        block = block + spdx_formats.contains.format(
            outer=layer_reference, inner=get_package_spdxref(package)) + '\n'
    return block

def get_document_block(image_obj):
    '''Return document related SPDX tag-values'''
    block = spdx_formats.spdx_version + '\n'
    block = block + spdx_formats.data_license + '\n'
    block = block + spdx_formats.spdx_id + '\n'
    block = block + spdx_formats.document_name.format(
        image_name=image_obj.get_human_readable_id()) + '\n'
    block = block + get_document_namespace(image_obj) + '\n'
    block = block + spdx_formats.license_list_version + '\n'
    block = block + spdx_formats.creator.format(
        version=get_git_rev_or_version()[1]) + '\n'
    block = block + spdx_formats.created.format(
        timestamp=datetime.datetime.utcnow().strftime(
            "%Y-%m-%dT%H:%M:%SZ")) + '\n'
    block = block + spdx_formats.document_comment + '\n'
    return block

def get_package_spdxref(package_obj):
    '''Given the package object, return an SPDX reference ID'''
    return 'SPDXRef-{}'.format(
        spdx_formats.package_id.format(
            name=package_obj.name,
            ver=package_obj.version).replace(':', '-', 1))

def get_document_block(image_obj):
    '''Return document related SPDX tag-values'''
    block = spdx_formats.spdx_version + '\n'
    block = block + spdx_formats.data_license + '\n'
    block = block + spdx_formats.spdx_id + '\n'
    block = block + spdx_formats.document_name.format(
        image_name=image_obj.get_human_readable_id()) + '\n'
    block = block + get_document_namespace(image_obj) + '\n'
    block = block + spdx_formats.license_list_version + '\n'
    block = block + spdx_formats.creator.format(
        version=get_git_rev_or_version()[1]) + '\n'
    block = block + spdx_formats.created.format(
        timestamp=datetime.datetime.utcnow().strftime(
            "%Y-%m-%dT%H:%M:%SZ")) + '\n'
    block = block + spdx_formats.document_comment + '\n'
    return block

# Add the package part for each package
        # There are no relationships to be listed here
        for layer_obj in image_obj.layers:
            for package_obj in layer_obj.packages:
                package_dict = package_obj.to_dict(template)
                # update the PackageLicenseDeclared with a LicenseRef string
                # only if the license data exists
                if ('PackageLicenseDeclared' in package_dict.keys() and
                        package_obj.pkg_license):
                    package_dict['PackageLicenseDeclared'] = \
                       get_license_ref(package_obj.pkg_license)
                if ('PackageCopyrightText' in package_dict.keys() and
                        package_obj.copyright):
                    package_dict['PackageCopyrightText'] = \
                        spdx_formats.block_text.format(
                            message=package_obj.copyright)
                # collect all the individual licenses
                if package_obj.pkg_license and package_obj.pkg_license \
                        not in licenses_found:
                    licenses_found.append(package_obj.pkg_license)
                report = report + get_main_block(
                    package_dict,
                    package_obj.origins.origins,
                    SPDXID=get_package_spdxref(package_obj),
                    PackageLicenseConcluded='NOASSERTION',
                    FilesAnalyzed='false') + '\n'
        return report + get_license_block(licenses_found)

def get_document_block(image_obj):
    '''Return document related SPDX tag-values'''
    block = spdx_formats.spdx_version + '\n'
    block = block + spdx_formats.data_license + '\n'
    block = block + spdx_formats.spdx_id + '\n'
    block = block + spdx_formats.document_name.format(
        image_name=image_obj.get_human_readable_id()) + '\n'
    block = block + get_document_namespace(image_obj) + '\n'
    block = block + spdx_formats.license_list_version + '\n'
    block = block + spdx_formats.creator.format(
        version=get_git_rev_or_version()[1]) + '\n'
    block = block + spdx_formats.created.format(
        timestamp=datetime.datetime.utcnow().strftime(
            "%Y-%m-%dT%H:%M:%SZ")) + '\n'
    block = block + spdx_formats.document_comment + '\n'
    return block

def get_document_block(image_obj):
    '''Return document related SPDX tag-values'''
    block = spdx_formats.spdx_version + '\n'
    block = block + spdx_formats.data_license + '\n'
    block = block + spdx_formats.spdx_id + '\n'
    block = block + spdx_formats.document_name.format(
        image_name=image_obj.get_human_readable_id()) + '\n'
    block = block + get_document_namespace(image_obj) + '\n'
    block = block + spdx_formats.license_list_version + '\n'
    block = block + spdx_formats.creator.format(
        version=get_git_rev_or_version()[1]) + '\n'
    block = block + spdx_formats.created.format(
        timestamp=datetime.datetime.utcnow().strftime(
            "%Y-%m-%dT%H:%M:%SZ")) + '\n'
    block = block + spdx_formats.document_comment + '\n'
    return block