set the waiting time.

        :Parameters:
            #. wait (number): The time delay between each attempt to lock. By default it's
               set to 0 to keeping the aquiring mechanism trying to acquire the lock without
               losing any time waiting. Setting wait to a higher value suchs as 0.05 seconds
               or higher can be very useful in special cases when many processes are trying
               to acquire the lock and one of them needs to hold it a release it at a higher
               frequency or rate.

def set_wait(self, wait):
        """
        set the waiting time.

        :Parameters:
            #. wait (number): The time delay between each attempt to lock. By default it's
               set to 0 to keeping the aquiring mechanism trying to acquire the lock without
               losing any time waiting. Setting wait to a higher value suchs as 0.05 seconds
               or higher can be very useful in special cases when many processes are trying
               to acquire the lock and one of them needs to hold it a release it at a higher
               frequency or rate.
        """
        try:
            wait = float(wait)
            assert wait>=0
        except:
            raise Exception('wait must be a positive number')
        self.__wait = wait