class_docstr: Backend storage for our "array of bits" using an mmap'd file.
  Please note that this has only been tested on Linux so far.
class_docstr_tok: ["Backend","storage","for","our","``","array","of","bits","''","using","an","mmap","'d","file",".","Please","note","that","this","has","only","been","tested","on","Linux","so","far","."]
docstr: clear bit number bitno - set it to false
code: def clear(self, bitno):
      """clear bit number bitno - set it to false"""
  
      byteno, bit_within_byteno = divmod(bitno, 8)
      mask = 1 << bit_within_byteno
      byte = self.mmap[byteno]
      byte &= Mmap_backend.effs - mask
      self.mmap[byteno] = byte
  
imports: import array
  import math
  import os
  import random
label_desc: Use image node_id 4 for calling the Mmap_backend obj's underlying member method code with example usage: obj.clear(bitno) without return types