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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 comparison_operator_query(comparison_operator):
 """Generate comparison operator checking function."""

    def _comparison_operator_query(expression):
        """Apply binary operator to expression."""
        def _apply_comparison_operator(index, expression=expression):
            """Return store key for documents that satisfy expression."""
            ev = expression() if callable(expression) else expression
            return [
                store_key
                for value, store_keys
                in index.get_index().items()
                if comparison_operator(value, ev)
                for store_key in store_keys
            ]
        return _apply_comparison_operator
    return _comparison_operator_query