code: def record_get_subfields(rec, tag, field_position_global=None,
                           field_position_local=None):
      
      field = record_get_field(
          rec, tag,
          field_position_global=field_position_global,
          field_position_local=field_position_local)
  
      return field[0]
docs: Return the subfield of the matching field.
  
      One has to enter either a global field position or a local field position.
  
      :return: a list of subfield tuples (subfield code, value).
      :rtype:  list