Option to ignore undefined tags

Would it be possible to have an option to ignore undefined tags instead of raising a yaml.constructor.ConstructorError?

Something like:

def construct_undefined(self, node):
    if ignore_undefined:
         return None
    raise ConstructorError(None, None,
            "could not determine a constructor for the tag %r" % node.tag,
            node.start_mark)

[ingydotnet]

This is trivial to do now:

import yaml

input = """\
- !foo hello world
- !bar 42
- OK
"""

yaml.add_multi_constructor('!', lambda loader, suffix, node: None)

print yaml.load(input)

[alanlivio]

Thanks, @nitzmahone. It worked.