docs: def delimiter_encodeseq(delimiter, encodeseq, charset):
      '''Coerce delimiter and encodeseq to unicode and verify that they are not
         the same'''
      delimiter = coerce_unicode(delimiter, charset)
      encodeseq = coerce_unicode(encodeseq, charset)
      if 1 != len(encodeseq):
          raise FSQEncodeError(errno.EINVAL, u'encode sequence must be 1'\
                               u' character, not {0}'.format(len(encodeseq)))
      if 1 != len(delimiter):
          raise FSQEncodeError(errno.EINVAL, u'delimiter must be 1 character,'\
                               u' not {0}'.format(len(delimiter)))
      if delimiter == encodeseq:
          raise FSQEncodeError(errno.EINVAL, u'delimiter and encoding may not'\
                               u' be the same: both: {0}'.format(encodeseq))
      try:
          delimiter.encode('ascii')
      except UnicodeEncodeError:
          raise FSQEncodeError(errno.EINVAL, u'delimiter must be ascii')
      try:
          encodeseq.encode('ascii')
      except UnicodeEncodeError:
          raise FSQEncodeError(errno.EINVAL, u'encodeseq must be ascii')
  
      return delimiter, encodeseq