def relop_bexp(env, node):
    """
    Relation operation boolean expression def for AST.
    interpret - runtime function for Evaluator (return result of applying the boolean operation to left and right values).
    Example: x > 56
    """
    left_value = node.left.interpret(env)
    right_value = node.right.interpret(env)
    if node.op == '<':
        value = left_value < right_value
    elif node.op == '<=':
        value = left_value <= right_value
    elif node.op == '>':
        value = left_value > right_value
    elif node.op == '>=':
        value = left_value >= right_value
    elif node.op == '==':
        value = left_value == right_value
    elif node.op == '!=':
        value = left_value != right_value
    else:
        raise RuntimeError('unknown operator: ' + node.op)
    return value