Improving conciseness of ipaddress factory functions.

Locate the ip_address, ip_network, ip_interface, and _prefix_from_ip_string entry points in the ipaddress implementation, then read their surrounding exception handling. Compare the proposed loop and suppression changes against the current behavior, including the existing error paths, and verify that the relevant ipaddress tests still pass.

Suggestion to refactor the 3 factory functions ip_address, ip_network, ip_interface.
In addition making a similar modification in the _prefix_from_ip_string function.

Currently the functions contain code which can be improved in terms of conciseness and extendability.

• try/catch containing a pass statement can be substituted with contextlib.suppress making the code more concise
• we can use a for loop which will iterate over the class objects to further increase conciseness

Current factory function implementations (docstrings not included for brevity)

def ip_address(address):
    try:
        return IPv4Address(address)
    except (AddressValueError, NetmaskValueError):
        pass

    try:
        return IPv6Address(address)
    except (AddressValueError, NetmaskValueError):
        pass

    raise ValueError(f'{address!r} does not appear to be an IPv4 or IPv6 address')


def ip_network(address, strict=True):
    try:
        return IPv4Network(address, strict)
    except (AddressValueError, NetmaskValueError):
        pass

    try:
        return IPv6Network(address, strict)
    except (AddressValueError, NetmaskValueError):
        pass

    raise ValueError(f'{address!r} does not appear to be an IPv4 or IPv6 network')


def ip_interface(address):
    try:
        return IPv4Interface(address)
    except (AddressValueError, NetmaskValueError):
        pass

    try:
        return IPv6Interface(address)
    except (AddressValueError, NetmaskValueError):
        pass

    raise ValueError(f'{address!r} does not appear to be an IPv4 or IPv6 interface')

Proposed function implementations

def ip_address(address):
    for ip_class in [IPv4Address, IPv6Address]:
        with contextlib.suppress(AddressValueError, NetmaskValueError):
            return ip_class(address)

    raise ValueError(f'{address!r} does not appear to be an IPv4 or IPv6 address')


def ip_network(address, strict=True):
    for network_class in [IPv4Network, IPv6Network]:
        with contextlib.suppress(AddressValueError, NetmaskValueError):
            return network_class(address, strict)

    raise ValueError(f'{address!r} does not appear to be an IPv4 or IPv6 network')


def ip_interface(address):
    for ip_interface_class in [IPv4Interface, IPv6Interface]:
        with contextlib.suppress(AddressValueError, NetmaskValueError):
            return ip_interface_class(address)

    raise ValueError(f'{address!r} does not appear to be an IPv4 or IPv6 interface')

current _prefix_from_ip_string function (docstrings and comments not included for brevity)

    @classmethod
    def _prefix_from_ip_string(cls, ip_str):
        try:
            ip_int = cls._ip_int_from_string(ip_str)
        except AddressValueError:
            cls._report_invalid_netmask(ip_str)

        try:
            return cls._prefix_from_ip_int(ip_int)
        except ValueError:
            pass

        ip_int ^= cls._ALL_ONES
        try:
            return cls._prefix_from_ip_int(ip_int)
        except ValueError:
            cls._report_invalid_netmask(ip_str)

Suggested improvement

    @classmethod
    def _prefix_from_ip_string(cls, ip_str):
        try:
            ip_int = cls._ip_int_from_string(ip_str)
        except AddressValueError:
            cls._report_invalid_netmask(ip_str)

        with contextlib.suppress(ValueError):
            return cls._prefix_from_ip_int(ip_int)

        ip_int ^= cls._ALL_ONES
        try:
            return cls._prefix_from_ip_int(ip_int)
        except ValueError:
            cls._report_invalid_netmask(ip_str)