def make_model(self):
        """Assemble text from the set of collected INDRA Statements.

        Returns
        -------
        stmt_strs : str
            Return the assembled text as unicode string. By default, the text
            is a single string consisting of one or more sentences with
            periods at the end.
        """
        stmt_strs = []
        for stmt in self.statements:
            if isinstance(stmt, ist.Modification):
                stmt_strs.append(_assemble_modification(stmt))
            elif isinstance(stmt, ist.Autophosphorylation):
                stmt_strs.append(_assemble_autophosphorylation(stmt))
            elif isinstance(stmt, ist.Association):
                stmt_strs.append(_assemble_association(stmt))
            elif isinstance(stmt, ist.Complex):
                stmt_strs.append(_assemble_complex(stmt))
            elif isinstance(stmt, ist.Influence):
                stmt_strs.append(_assemble_influence(stmt))
            elif isinstance(stmt, ist.RegulateActivity):
                stmt_strs.append(_assemble_regulate_activity(stmt))
            elif isinstance(stmt, ist.RegulateAmount):
                stmt_strs.append(_assemble_regulate_amount(stmt))
            elif isinstance(stmt, ist.ActiveForm):
                stmt_strs.append(_assemble_activeform(stmt))
            elif isinstance(stmt, ist.Translocation):
                stmt_strs.append(_assemble_translocation(stmt))
            elif isinstance(stmt, ist.Gef):
                stmt_strs.append(_assemble_gef(stmt))
            elif isinstance(stmt, ist.Gap):
                stmt_strs.append(_assemble_gap(stmt))
            elif isinstance(stmt, ist.Conversion):
                stmt_strs.append(_assemble_conversion(stmt))
            else:
                logger.warning('Unhandled statement type: %s.' % type(stmt))
        if stmt_strs:
            return ' '.join(stmt_strs)
        else:
            return ''
Assemble text from the set of collected INDRA Statements.

        Returns
        -------
        stmt_strs : str
            Return the assembled text as unicode string. By default, the text
            is a single string consisting of one or more sentences with
            periods at the end.