function.py 文件源码

def __new__(cls, variables, expr):
        from sympy.sets.sets import FiniteSet
        try:
            for v in variables if iterable(variables) else [variables]:
                if not v.is_Symbol:
                    raise TypeError("v is not a symbol")
        except (AssertionError, AttributeError):
            raise ValueError('variable is not a Symbol: %s' % v)
        try:
            variables = Tuple(*variables)
        except TypeError:
            variables = Tuple(variables)
        if len(variables) == 1 and variables[0] == expr:
            return S.IdentityFunction

        obj = Expr.__new__(cls, Tuple(*variables), S(expr))
        obj.nargs = FiniteSet(len(variables))
        return obj