code: def to_mllp(self, encoding_chars=None, trailing_children=False):
          
          if encoding_chars is None:
              encoding_chars = self.encoding_chars
  
          return "{0}{1}{2}{3}{2}".format(MLLP_ENCODING_CHARS.SB,
                                          self.to_er7(encoding_chars, trailing_children),
                                          MLLP_ENCODING_CHARS.CR,
                                          MLLP_ENCODING_CHARS.EB)
docs: Returns the er7 representation of the message wrapped with mllp encoding characters
  
          :type encoding_chars: ``dict``
          :param encoding_chars: a dictionary containing the encoding chars or None to use the default
              (see :func:`get_default_encoding_chars <hl7apy.get_default_encoding_chars>`)
  
          :type trailing_children: ``bool``
          :param trailing_children: if ``True``, trailing children will be added even if their value is ``None``
  
          :return: the ER7-encoded string wrapped with the mllp encoding characters