docs: def _index_idiom(el_name, index, alt=None):
      """
      Generate string where `el_name` is indexed by `index` if there are enough
      items or `alt` is returned.
  
      Args:
          el_name (str): Name of the `container` which is indexed.
          index (int): Index of the item you want to obtain from container.
          alt (whatever, default None): Alternative value.
  
      Returns:
          str: Python code.
  
      Live example::
          >>> import generator as g
          >>> print g._index_idiom("xex", 0)
              # pick element from list
              xex = xex[0] if xex else None
          >>> print g._index_idiom("xex", 1, "something")
          # pick element from list
          xex = xex[1] if len(xex) - 1 >= 1 else 'something'
      """
      el_index = "%s[%d]" % (el_name, index)
  
      if index == 0:
          cond = "%s" % el_name
      else:
          cond = "len(%s) - 1 >= %d" % (el_name, index)
  
      output = IND + "# pick element from list\n"
  
      return output + IND + "%s = %s if %s else %s\n\n" % (
          el_name,
          el_index,
          cond,
          repr(alt)
      )