code: def record_delete_subfield_from(rec, tag, subfield_position,
                                  field_position_global=None,
                                  field_position_local=None):
      
      subfields = record_get_subfields(
          rec, tag,
          field_position_global=field_position_global,
          field_position_local=field_position_local)
  
      try:
          del subfields[subfield_position]
      except IndexError:
          raise InvenioBibRecordFieldError(
              "The record does not contain the subfield "
              "'%(subfieldIndex)s' inside the field (local: "
              "'%(fieldIndexLocal)s, global: '%(fieldIndexGlobal)s' ) of tag "
              "'%(tag)s'." %
              {"subfieldIndex": subfield_position,
               "fieldIndexLocal": str(field_position_local),
               "fieldIndexGlobal": str(field_position_global),
               "tag": tag})
      if not subfields:
          if field_position_global is not None:
              for position, field in enumerate(rec[tag]):
                  if field[4] == field_position_global:
                      del rec[tag][position]
          else:
              del rec[tag][field_position_local]
  
          if not rec[tag]:
              del rec[tag]
docs: Delete subfield from position specified.
  
      Specify the subfield by tag, field number and subfield position.