code: def _assemble_conversion(stmt):
      
      reactants = _join_list([_assemble_agent_str(r) for r in stmt.obj_from])
      products = _join_list([_assemble_agent_str(r) for r in stmt.obj_to])
  
      if stmt.subj is not None:
          subj_str = _assemble_agent_str(stmt.subj)
          stmt_str = '%s catalyzes the conversion of %s into %s' % \
              (subj_str, reactants, products)
      else:
          stmt_str = '%s is converted into %s' % (reactants, products)
      return _make_sentence(stmt_str)
docs: Assemble a Conversion statement into text.