'check a path for existence and properties.
Without arguments, return True if the path exists, otherwise False.
valid checkers::
file=1    # is a file
file=0    # is not a file (may not even exist)
dir=1     # is a dir
link=1    # is a link
exists=1  # exists
You can specify multiple checker definitions, for example::
path.check(file=1, link=1)  # a link pointing to a file'

def check(self, **kw):

    if (not kw):
        kw = {'exists': 1}
    return self.Checkers(self)._evaluate(kw)
