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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def eq_(self, value):
        ''' Creates a query expression where ``this field == value``

            .. note:: The prefered usage is via an operator: ``User.name == value``
        '''
        if isinstance(value, QueryField):
            return self.__cached_id == value.__cached_id
        return QueryExpression({ self : self.get_type().wrap_value(value) })