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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 _binary_exp(expression, op):
 # type: (QuilParser.ExpressionContext, Callable) -> Number """ Apply an operator to two expressions. Start by evaluating both sides of the operator. """

    [arg1, arg2] = expression.expression()
    return op(_expression(arg1), _expression(arg2))