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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 expression(self):
 """ A relation algebra expression. An expression is either a relation or a combination of relations that uses the previously defined operators and follows precedence rules. """

        return operatorPrecedence(self.relation, [
            (self.unary_op, 1, opAssoc.RIGHT),
            (self.binary_op_p1, 2, opAssoc.LEFT),
            (self.binary_op_p2, 2, opAssoc.LEFT)])