def to_instance(cls, ob, default=None, strict=False):
        """Encode a GeoJSON dict into an GeoJSON object.
        Assumes the caller knows that the dict should satisfy a GeoJSON type.

        :param cls: Dict containing the elements to be encoded into a GeoJSON
        object.
        :type cls: dict
        :param ob: GeoJSON object into which to encode the dict provided in
        `cls`.
        :type ob: GeoJSON
        :param default: A default instance to append the content of the dict
        to if none is provided.
        :type default: GeoJSON
        :param strict: Raise error if unable to coerce particular keys or
        attributes to a valid GeoJSON structure.
        :type strict: bool
        :return: A GeoJSON object with the dict's elements as its constituents.
        :rtype: GeoJSON
        :raises TypeError: If the input dict contains items that are not valid
        GeoJSON types.
        :raises UnicodeEncodeError: If the input dict contains items of a type
        that contain non-ASCII characters.
        :raises AttributeError: If the input dict contains items that are not
        valid GeoJSON types.
        """
        if ob is None and default is not None:
            instance = default()
        elif isinstance(ob, GeoJSON):
            instance = ob
        else:
            mapping = to_mapping(ob)
            d = {}
            for k in mapping:
                d[k] = mapping[k]
            try:
                type_ = d.pop("type")
                try:
                    type_ = str(type_)
                except UnicodeEncodeError:
                    # If the type contains non-ascii characters, we can assume
                    # it's not a valid GeoJSON type
                    raise AttributeError(f"{type_} is not a GeoJSON type")
                geojson_factory = getattr(geojson.factory, type_)
                instance = geojson_factory(**d)
            except (AttributeError, KeyError) as invalid:
                if strict:
                    raise ValueError(
                        f"Cannot coerce {ob!r} into "
                        f"a valid GeoJSON structure: {invalid}"
                    )
                instance = ob
        return instance
Encode a GeoJSON dict into an GeoJSON object.
        Assumes the caller knows that the dict should satisfy a GeoJSON type.

        :param cls: Dict containing the elements to be encoded into a GeoJSON
        object.
        :type cls: dict
        :param ob: GeoJSON object into which to encode the dict provided in
        `cls`.
        :type ob: GeoJSON
        :param default: A default instance to append the content of the dict
        to if none is provided.
        :type default: GeoJSON
        :param strict: Raise error if unable to coerce particular keys or
        attributes to a valid GeoJSON structure.
        :type strict: bool
        :return: A GeoJSON object with the dict's elements as its constituents.
        :rtype: GeoJSON
        :raises TypeError: If the input dict contains items that are not valid
        GeoJSON types.
        :raises UnicodeEncodeError: If the input dict contains items of a type
        that contain non-ASCII characters.
        :raises AttributeError: If the input dict contains items that are not
        valid GeoJSON types.
        
geojson/base.py