code: def write(self, filename=None, skipempty=False):
          
  
          with open(self.filename(filename, ext='mdp'), 'w') as mdp:
              for k,v in self.items():
                  if k[0] == 'B':        # blank line
                      mdp.write("\n")
                  elif k[0] == 'C':      # comment
                      mdp.write("; {v!s}\n".format(**vars()))
                  else:                  # parameter = value
                      if skipempty and (v == '' or v is None):
                          continue
                      if isinstance(v, six.string_types) or not hasattr(v, '__iter__'):
                          mdp.write("{k!s} = {v!s}\n".format(**vars()))
                      else:
                           mdp.write("{} = {}\n".format(k,' '.join(map(str, v))))
docs: Write mdp file to *filename*.
  
          :Keywords:
             *filename*
                 output mdp file; default is the filename the mdp
                 was read from
             *skipempty* : boolean
                 ``True`` removes any parameter lines from output that
                 contain empty values [``False``]
  
          .. Note:: Overwrites the file that the mdp was read from if no
                    *filename* supplied.