def __init__(self, function, argument):
        assert isinstance(function, Expression), "%s is not an Expression" % function
        assert isinstance(argument, Expression), "%s is not an Expression" % argument
        self.function = function
        self.argument = argument
:param function: ``Expression``, for the function expression
dataset/ETHPy150Open nltk/nltk/nltk/sem/logic.py/ApplicationExpression.__init__