Restore GFF3 entry to original format

        Returns:
            str: properly formatted string containing the GFF3 entry

def write(self):
        """Restore GFF3 entry to original format

        Returns:
            str: properly formatted string containing the GFF3 entry
        """

        none_type = type(None)

        # Format attributes for writing
        attrs = self.attribute_string()

        # Place holder if field value is NoneType
        for attr in self.__dict__.keys():
            if type(attr) == none_type:
                setattr(self, attr, '.')

        # Format entry for writing
        fstr = '{0}\t{1}\t{2}\t{3}\t{4}\t{5}\t{6}\t{7}\t{8}{9}'\
               .format(self.seqid, self.source, self.type, str(self.start),
                       str(self.end), self._score_str, self.strand, 
                       self.phase, attrs, os.linesep)

        return fstr