docs: def countbit(self, name, start=None, size=None):
          """
          Returns the count of set bits in the value of ``key``.  Optional
          ``start`` and ``size`` paramaters indicate which bytes to consider.
  
          Similiar with **Redis.BITCOUNT**
  
          :param string name: the key name
          :param int start: Optional, if start is negative, count from start'th
           character from the end of string.
          :param int size: Optional, if size is negative, then that many
           characters will be omitted from the end of string.
          :return: the count of the bit 1
          :rtype: int
          
          >>> ssdb.set('bit_test', 1)
          True
          >>> ssdb.countbit('bit_test')
          3
          >>> ssdb.set('bit_test','1234567890')
          True
          >>> ssdb.countbit('bit_test', 0, 1)
          3
          >>> ssdb.countbit('bit_test', 3, -3)
          16
          """
          if start is not None and size is not None:
              start = get_integer('start', start)
              size = get_integer('size', size)
              return self.execute_command('countbit', name, start, size)
          elif start is not None:
              start = get_integer('start', start)            
              return self.execute_command('countbit', name, start)
          return self.execute_command('countbit', name)