docs: def _read_git_tags(
          default_version=DEFAULT_VERSION,
          git_command=('git', 'tag'),
  ):
      """tries to find current git tag
  
      Notes:
          git_command exposed for testing null case
  
      Args:
          default_version (str): what version to make
          git_command (:obj:`list`): subprocess command
  
      Retruns:
          str: latest version found, or default
  
      Warns:
          exceptions.ProsperDefaultVersionWarning: git version not found
  
      """
      try:
          current_tags = check_output(git_command).splitlines()
      except Exception:  # pragma: no cover
          raise
  
      if not current_tags[0]:
          warnings.warn(
              'Unable to resolve current version',
              exceptions.ProsperDefaultVersionWarning)
          return default_version
  
      latest_version = semantic_version.Version(default_version)
      for tag in current_tags:
          tag_str = decode(tag, 'utf-8').replace('v', '')
          try:
              tag_ver = semantic_version.Version(tag_str)
          except Exception:  # pragma: no cover
              continue  # invalid tags ok, but no release
  
          if tag_ver > latest_version:
              latest_version = tag_ver
  
      return str(latest_version)