How to use the conda._vendor.auxlib.entity.StringField function in conda

def dist_str(self):
        return "%s::%s-%s-%s" % (self.channel.canonical_name, self.name, self.version, self.build)

    def dist_fields_dump(self):
        return {
            "base_url": self.channel.base_url,
            "build_number": self.build_number,
            "build_string": self.build,
            "channel": self.channel.name,
            "dist_name": self.dist_str().split(":")[-1],
            "name": self.name,
            "platform": self.subdir,
            "version": self.version,
        }

    arch = StringField(required=False, nullable=True)  # so legacy
    platform = EnumField(Platform, required=False, nullable=True)  # so legacy

    depends = ListField(string_types, default=())
    constrains = ListField(string_types, default=())

    track_features = _FeaturesField(required=False, default=(), default_in_dump=False)
    features = _FeaturesField(required=False, default=(), default_in_dump=False)

    noarch = NoarchField(NoarchType, required=False, nullable=True, default=None,
                         default_in_dump=False)  # TODO: rename to package_type
    preferred_env = StringField(required=False, nullable=True, default=None, default_in_dump=False)

    license = StringField(required=False, nullable=True, default=None, default_in_dump=False)
    license_family = StringField(required=False, nullable=True, default=None,
                                 default_in_dump=False)
    package_type = PackageTypeField()

build = StringField(aliases=('build_string',))
    build_number = IntegerField()

    # the canonical code abbreviation for PackageRef is `pref`
    # fields required to uniquely identifying a package

    channel = ChannelField(aliases=('schannel',))
    subdir = SubdirField()
    fn = FilenameField(aliases=('filename',))

    md5 = StringField(default=None, required=False, nullable=True, default_in_dump=False)
    legacy_bz2_md5 = StringField(default=None, required=False, nullable=True,
                                 default_in_dump=False)
    legacy_bz2_size = IntegerField(required=False, nullable=True, default_in_dump=False)
    url = StringField(default=None, required=False, nullable=True, default_in_dump=False)
    sha256 = StringField(default=None, required=False, nullable=True, default_in_dump=False)

    @property
    def schannel(self):
        return self.channel.canonical_name

    @property
    def _pkey(self):
        try:
            return self.__pkey
        except AttributeError:
            __pkey = self.__pkey = [
                self.channel.canonical_name, self.subdir, self.name,
                self.version, self.build_number, self.build
            ]
            # NOTE: fn is included to distinguish between .conda and .tar.bz2 packages
            if context.separate_format_cache:

executable_paths = ListField(string_types, required=False, nullable=True)
    softlink_paths = ListField(string_types, required=False, nullable=True)


class PackageMetadata(Entity):
    # from info/package_metadata.json
    package_metadata_version = IntegerField()
    noarch = ComposableField(Noarch, required=False, nullable=True)
    preferred_env = ComposableField(PreferredEnv, required=False, nullable=True, default=None,
                                    default_in_dump=False)


class PackageInfo(ImmutableEntity):

    # attributes external to the package tarball
    extracted_package_dir = StringField()
    channel = ComposableField(Channel)
    repodata_record = ComposableField(PackageRecord)
    url = StringField()

    # attributes within the package tarball
    index_json_record = ComposableField(IndexJsonRecord)
    icondata = StringField(required=False, nullable=True)
    package_metadata = ComposableField(PackageMetadata, required=False, nullable=True)
    paths_data = ComposableField(PathsData)

    def dist_str(self):
        return "%s::%s-%s-%s" % (self.channel.canonical_name, self.name, self.version, self.build)

    @property
    def name(self):
        return self.repodata_record.name

md5 = StringField(required=False, nullable=True)
    name = StringField()
    noarch = NoarchField(NoarchType, required=False, nullable=True)
    platform = EnumField(Platform, required=False, nullable=True)
    requires = ListField(string_types, required=False)
    size = IntegerField(required=False)
    subdir = StringField(required=False)
    track_features = StringField(required=False)
    version = StringField()

    fn = StringField(required=False, nullable=True)
    schannel = StringField(required=False, nullable=True)
    channel = StringField(required=False, nullable=True)
    priority = IntegerField(required=False)
    url = StringField(required=False, nullable=True)
    auth = StringField(required=False, nullable=True)

    files = ListField(string_types, default=(), required=False)
    link = ComposableField(Link, required=False)

    with_features_depends = MapField(required=False)
    preferred_env = StringField(default=None, required=False, nullable=True)

"platform": self.subdir,
            "version": self.version,
        }

    arch = StringField(required=False, nullable=True)  # so legacy
    platform = EnumField(Platform, required=False, nullable=True)  # so legacy

    depends = ListField(string_types, default=())
    constrains = ListField(string_types, default=())

    track_features = _FeaturesField(required=False, default=(), default_in_dump=False)
    features = _FeaturesField(required=False, default=(), default_in_dump=False)

    noarch = NoarchField(NoarchType, required=False, nullable=True, default=None,
                         default_in_dump=False)  # TODO: rename to package_type
    preferred_env = StringField(required=False, nullable=True, default=None, default_in_dump=False)

    license = StringField(required=False, nullable=True, default=None, default_in_dump=False)
    license_family = StringField(required=False, nullable=True, default=None,
                                 default_in_dump=False)
    package_type = PackageTypeField()

    @property
    def is_unmanageable(self):
        return self.package_type in PackageType.unmanageable_package_types()

    timestamp = TimestampField()

    @property
    def combined_depends(self):
        from .match_spec import MatchSpec
        result = {ms.name: ms for ms in MatchSpec.merge(self.depends)}

class LeasedPathEntry(Entity):
    """
        _path: short path for the leased path, using forward slashes
        target_path: the full path to the executable in the private env
        target_prefix: the full path to the private environment
        leased_path: the full path for the lease in the root prefix
        package_name: the package holding the lease
        leased_path_type: application_entry_point

    """

    _path = StringField()
    target_path = StringField()
    target_prefix = StringField()
    leased_path = StringField()
    package_name = StringField()
    leased_path_type = EnumField(LeasedPathType)

channel_override=value.channel.canonical_name)
            elif isinstance(value, Channel):
                return Dist.from_url(value.url())
            else:
                return Dist.from_string(value)
        else:
            return super(DistType, cls).__call__(*args, **kwargs)


@with_metaclass(DistType)
class Dist(Entity):
    _lazy_validate = True

    channel = StringField(required=False, nullable=True, immutable=True)

    dist_name = StringField(immutable=True)
    name = StringField(immutable=True)
    version = StringField(immutable=True)
    build_string = StringField(immutable=True)
    build_number = IntegerField(immutable=True)

    base_url = StringField(required=False, nullable=True, immutable=True)
    platform = StringField(required=False, nullable=True, immutable=True)

    def __init__(self, channel, dist_name=None, name=None, version=None, build_string=None,
                 build_number=None, base_url=None, platform=None):
        super(Dist, self).__init__(channel=channel,
                                   dist_name=dist_name,
                                   name=name,
                                   version=version,
                                   build_string=build_string,
                                   build_number=build_number,

elif isinstance(value, PackageInfo):
                return Dist.from_string(value.repodata_record.fn,
                                        channel_override=value.channel.canonical_name)
            elif isinstance(value, Channel):
                return Dist.from_url(value.url())
            else:
                return Dist.from_string(value)
        else:
            return super(DistType, cls).__call__(*args, **kwargs)


@with_metaclass(DistType)
class Dist(Entity):
    _lazy_validate = True

    channel = StringField(required=False, nullable=True, immutable=True)

    dist_name = StringField(immutable=True)
    name = StringField(immutable=True)
    version = StringField(immutable=True)
    build_string = StringField(immutable=True)
    build_number = IntegerField(immutable=True)

    base_url = StringField(required=False, nullable=True, immutable=True)
    platform = StringField(required=False, nullable=True, immutable=True)

    def __init__(self, channel, dist_name=None, name=None, version=None, build_string=None,
                 build_number=None, base_url=None, platform=None):
        super(Dist, self).__init__(channel=channel,
                                   dist_name=dist_name,
                                   name=name,
                                   version=version,

return super(DistType, cls).__call__(*args, **kwargs)


@with_metaclass(DistType)
class Dist(Entity):
    _lazy_validate = True

    channel = StringField(required=False, nullable=True, immutable=True)

    dist_name = StringField(immutable=True)
    name = StringField(immutable=True)
    version = StringField(immutable=True)
    build_string = StringField(immutable=True)
    build_number = IntegerField(immutable=True)

    base_url = StringField(required=False, nullable=True, immutable=True)
    platform = StringField(required=False, nullable=True, immutable=True)

    def __init__(self, channel, dist_name=None, name=None, version=None, build_string=None,
                 build_number=None, base_url=None, platform=None):
        super(Dist, self).__init__(channel=channel,
                                   dist_name=dist_name,
                                   name=name,
                                   version=version,
                                   build_string=build_string,
                                   build_number=build_number,
                                   base_url=base_url,
                                   platform=platform)

    def to_package_ref(self):
        return PackageRef(
            channel=self.channel,

subdir = StringField(required=False)
    track_features = StringField(required=False)
    version = StringField()

    fn = StringField(required=False, nullable=True)
    schannel = StringField(required=False, nullable=True)
    channel = StringField(required=False, nullable=True)
    priority = IntegerField(required=False)
    url = StringField(required=False, nullable=True)
    auth = StringField(required=False, nullable=True)

    files = ListField(string_types, default=(), required=False)
    link = ComposableField(Link, required=False)

    with_features_depends = MapField(required=False)
    preferred_env = StringField(default=None, required=False, nullable=True)