code: def make_model(self):
          
          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 ''
docs: 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.