core.py 文件源码

def __new__(cls, variable, value):
        if not isinstance(variable, Variable):
            raise TypeError("variable must be of type Variable")

        _valid_instances = (Nil, Variable,
                            IndexedVariable, IndexedElement,
                            Tuple,
                            int, float, bool, complex, str,
                            Boolean, sp_Integer, sp_Float)

        if not isinstance(value, _valid_instances):
            raise TypeError('non-valid instance for value, '
                            'given {0}'.format(type(value)))

        return Basic.__new__(cls, variable, value)