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4.4.4 Logical Operators

        A logical value is True or False. The logical operators yield True or False, depending upon the value of logical
        operands on either side. A value other than 0 and None evaluates to True while zero evaluates to False. Therefore,
        1,  "bb", and  -1 are interpreted as  True but  0 and  None are interpreted as  False. There are three  logical
        operators: and, or, and not. Note that all three operators are keywords and are used in lowercase only. Further, in
        an expression, the precedence of the operators in decreasing order is: not, and, or. These operators may be used to
        express relationships between relational expressions. For detailed description of these operators, see Table 4.4: Logical
        Operators.

                                                 Table 4.4: Logical Operators
                  (Assume the value of a, b, and c to be 10, 5, and -2, respectively for computations in the table)

         Operator     Explanation                                    Examples

         and          It yields True if both the operands yield True, and  >>> True and True
                      False otherwise.                                   True

                                                                     >>> True and False
                                                                         False
                                                                     >>> a > b and b > c
                                                                         True
                                                                     >>> a < b and b > c
                                                                         False
                                                                     >>> a < b and b < c
                                                                         False
         or           It yields True if either of the two operands yields  >>> True or True
                      True, and False otherwise.                         True

                                                                     >>> False or True
                                                                         True
                                                                     >>> False or False
                                                                         False
                                                                     >>> a > b or b > c
                                                                         True
                                                                     >>> a < b or b > c
                                                                         True
                                                                     >>> a < b or b < c
                                                                         False
         not          Not True yields False and Not False yields  >>> not True
                      True.                                              False
                                                                     >>> not False
                                                                         True
                                                                     >>> not a > c
                                                                         False
                                                                     >>> test = 0
                                                                     >>> not test
                                                                         True



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