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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 maybe_expression(s):
 """ loose checking if s is a pytables-acceptable expression """

    if not isinstance(s, str):
        return False
    ops = ExprVisitor.binary_ops + ExprVisitor.unary_ops + ('=',)

    # make sure we have an op at least
    return any(op in s for op in ops)