How to use the pystac.link.Link.from_dict function in pystac

license=license,
                                stac_extensions=stac_extensions,
                                keywords=keywords,
                                version=version,
                                providers=providers,
                                properties=properties,
                                summaries=summaries)

        has_self_link = False
        for l in d['links']:
            has_self_link |= l['rel'] == 'self'
            if l['rel'] == 'root':
                # Remove the link that's generated in Catalog's constructor.
                collection.remove_links('root')

            collection.add_link(Link.from_dict(l))

        if not has_self_link and href is not None:
            collection.add_link(Link.self_href(href))

        return collection

def from_dict(d):
        """Constructs an ItemCollection from a dict.

        Returns:
            ItemCollection: The ItemCollection deserialized from the JSON dict.
        """
        features = [Item.from_dict(feature) for feature in d['features']]
        ic = ItemCollection(features)
        if 'links' in d.keys():
            for link in d['links']:
                ic.add_link(Link.from_dict(link))
        return ic

if datetime is None:
            raise STACError('Item dict is missing a "datetime" property in the "properties" field')
        datetime = dateutil.parser.parse(datetime)

        item = Item(id=id,
                    geometry=geometry,
                    bbox=bbox,
                    datetime=datetime,
                    properties=properties,
                    stac_extensions=stac_extensions,
                    collection=collection_id)

        has_self_link = False
        for l in d['links']:
            has_self_link |= l['rel'] == 'self'
            item.add_link(Link.from_dict(l))

        if not has_self_link and href is not None:
            item.add_link(Link.self_href(href))

        for k, v in d['assets'].items():
            asset = Asset.from_dict(v)
            asset.set_owner(item)
            item.assets[k] = asset

        return item

def from_dict(cls, d, href=None, root=None):
        id = d['id']
        description = d['description']
        title = d.get('title')

        cat = Catalog(id=id, description=description, title=title)

        has_self_link = False
        for l in d['links']:
            has_self_link |= l['rel'] == 'self'
            if l['rel'] == 'root':
                # Remove the link that's generated in Catalog's constructor.
                cat.remove_links('root')

            cat.add_link(Link.from_dict(l))

        if not has_self_link and href is not None:
            cat.add_link(Link.self_href(href))

        return cat