docs: def _writeRmc(self, filelike, specfile):
          """Writes the ``.rmc`` container entry of the specified specfile as an
          human readable and pretty formatted xml string.
  
          :param filelike: path to a file (str) or a file-like object
          :param specfile: name of an ms-run file present in ``self.info``
          """
          xmlString = ETREE.tostring(self.rmc[specfile], pretty_print=True)
          filelike.write(xmlString)