code: def eval(self, construct):
          
          data = clips.data.DataObject(self._env)
  
          if lib.EnvEval(self._env, construct.encode(), data.byref) != 1:
              raise CLIPSError(self._env)
  
          return data.value
docs: Evaluate an expression returning its value.
  
          The Python equivalent of the CLIPS eval command.