'Instantiate a new IPv4 network object.
Args:
address: A string or integer representing the IP [& network].
\'192.0.2.0/24\'
\'192.0.2.0/255.255.255.0\'
\'192.0.0.2/0.0.0.255\'
are all functionally the same in IPv4. Similarly,
\'192.0.2.1\'
\'192.0.2.1/255.255.255.255\'
\'192.0.2.1/32\'
are also functionally equivalent. That is to say, failing to
provide a subnetmask will create an object with a mask of /32.
If the mask (portion after the / in the argument) is given in
dotted quad form, it is treated as a netmask if it starts with a
non-zero field (e.g. /255.0.0.0 == /8) and as a hostmask if it
starts with a zero field (e.g. 0.255.255.255 == /8), with the
single exception of an all-zero mask which is treated as a
netmask == /0. If no mask is given, a default of /32 is used.
Additionally, an integer can be passed, so
IPv4Network(\'192.0.2.1\') == IPv4Network(3221225985)
or, more generally
IPv4Interface(int(IPv4Interface(\'192.0.2.1\'))) ==
IPv4Interface(\'192.0.2.1\')
Raises:
AddressValueError: If ipaddress isn\'t a valid IPv4 address.
NetmaskValueError: If the netmask isn\'t valid for
an IPv4 address.
ValueError: If strict is True and a network address is not
supplied.'

def __init__(self, address, strict=True):

    _BaseNetwork.__init__(self, address)
    if isinstance(address, (_compat_int_types, bytes)):
        self.network_address = IPv4Address(address)
        (self.netmask, self._prefixlen) = self._make_netmask(self._max_prefixlen)
        return
    if isinstance(address, tuple):
        if (len(address) > 1):
            arg = address[1]
        else:
            arg = self._max_prefixlen
        self.network_address = IPv4Address(address[0])
        (self.netmask, self._prefixlen) = self._make_netmask(arg)
        packed = int(self.network_address)
        if ((packed & int(self.netmask)) != packed):
            if strict:
                raise ValueError((u'%s    has    host    bits    set' % self))
            else:
                self.network_address = IPv4Address((packed & int(self.netmask)))
        return
    addr = _split_optional_netmask(address)
    self.network_address = IPv4Address(self._ip_int_from_string(addr[0]))
    if (len(addr) == 2):
        arg = addr[1]
    else:
        arg = self._max_prefixlen
    (self.netmask, self._prefixlen) = self._make_netmask(arg)
    if strict:
        if (IPv4Address((int(self.network_address) & int(self.netmask))) != self.network_address):
            raise ValueError((u'%s    has    host    bits    set' % self))
    self.network_address = IPv4Address((int(self.network_address) & int(self.netmask)))
    if (self._prefixlen == (self._max_prefixlen - 1)):
        self.hosts = self.__iter__
