def _number_of_set_bits_to_ipv4_netmask(set_bits):
 return cidr_to_ipv4_netmask(_number_of_set_bits(set_bits))

def _number_of_set_bits_to_ipv4_netmask ( set_bits ) : return cidr_to_ipv4_netmask ( _number_of_set_bits ( set_bits ) )
returns an ipv4 netmask from the integer representation of that mask .