code: def _get_random_string(length=44,
                         allowed_chars='abcdefghijklmnopqrstuvwxyz'
                         'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789',
                         secret_key=settings.secret_key_bytes()):
      
      secret_key = _ensure_bytes(secret_key)
      _reseed_if_needed(using_sysrandom, secret_key)
      return ''.join(random.choice(allowed_chars) for i in range(length))
docs: Return a securely generated random string.
      With the a-z, A-Z, 0-9 character set:
      Length 12 is a 71-bit value. log_2((26+26+10)^12) =~ 71
      Length 44 is a 261-bit value. log_2((26+26+10)^44) = 261