class_docstr: :class:`DatasetVersion` has two constructors: :func:`.from_json` and
  :func:`.get_region`.
  
  Parameters
  ----------
  url : :obj:`dict` or :obj:`str`
      Nested dictionary of URLs containing key: value pairs, like
      ``cloud: {region: url}`` if using :func:`.from_json` constructor,
      or a string with the URL from appropriate region if using the
      :func:`.get_region` constructor.
  version : :obj:`str`, optional
      String of dataset version, if not ``None``.
  reference_genome : :obj:`str`, optional
      String of dataset reference genome, if not ``None``.
docstr: Get versions of a :class:`.Dataset` in the specified region, if they
  exist.
  
  Parameters
  ----------
  name : :obj:`str`
      Name of dataset.
  versions : :class:`list` of :class:`.DatasetVersion`
      List of DatasetVersion objects where the value for :attr:`.url`
      is a :obj:`dict` containing key: value pairs, like ``region: url``.
  region : :obj:`str`
      Region from which to access data, available regions given in
      :attr:`hail.experimental.DB._valid_regions`, currently either
      ``'us'`` or 'eu'.
  
  Returns
  -------
  available_versions : :class:`list` of :class:`.DatasetVersion`
      List of available versions of a class:`.Dataset` for region.
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code: def get_region(
      name: str, versions: List["DatasetVersion"], region: str
  ) -> List["DatasetVersion"]:
      """Get versions of a :class:`.Dataset` in the specified region, if they
      exist.
  
      Parameters
      ----------
      name : :obj:`str`
          Name of dataset.
      versions : :class:`list` of :class:`.DatasetVersion`
          List of DatasetVersion objects where the value for :attr:`.url`
          is a :obj:`dict` containing key: value pairs, like ``region: url``.
      region : :obj:`str`
          Region from which to access data, available regions given in
          :attr:`hail.experimental.DB._valid_regions`, currently either
          ``'us'`` or 'eu'.
  
      Returns
      -------
      available_versions : :class:`list` of :class:`.DatasetVersion`
          List of available versions of a class:`.Dataset` for region.
      """
      available_versions = []
      for version in versions:
          if version.in_region(name, region):
              version.url = version.url[region]
              available_versions.append(version)
      return available_versions
  
imports: import json
  import os
  import warnings
  from typing import Iterable, List, Optional, Set, Tuple, Union
  import hail
  import pkg_resources
  from hailtop.utils import external_requests_client_session, retry_response_returning_functions
  from .lens import MatrixRows, TableRows
  from ..expr import StructExpression
  from ..matrixtable import MatrixTable, matrix_table_type
  from ..table import Table, table_type
  from ..typecheck import oneof, typecheck_method
  from ..utils.java import Env, info
label_desc: Use image node_id 2 for calling the DatasetVersion obj's underlying member method code with example usage: obj.get_region(name, versions, region) and returns: available_versions