[none] kbd-scrolllock kbd-numlock kbd-capslock kbd-kanalock kbd-shiftlock kbd-altgrlock kbd-ctrllock kbd-altlock kbd-shiftllock kbd-shiftrlock kbd-ctrlllock kbd-ctrlrlock 
  "   ˆl–Ãa¾”Ên-j~àY¸&ÔÅ£ÄƒO=ÃÂ 	¸    class SetMixin(object):

    """
    Mix-in for sets.  You must define __iter__, add, remove
    """

    def __len__(self):
        length = 0
        for item in self:
            length += 1
        return length

    def __contains__(self, item):
        for has_item in self:
            if item == has_item:
                return True
        return False

    def issubset(self, other):
        for item in other:
            if item not in self:
                return False
        return True

    __le__ = issubset

    def issuperset(self, other):
        for item in self:
            if item not in other:
                return False
        return True

    __ge__ = issuperset

    def union(self, other):
        return self | other

    def __or__(self, other):
        new = self.copy()
        new |= other
        return new
    
    def intersection(self, other):
        return self & other

    def __and__(self, other):
        new = self.copy()
        new &= other
        return new

    def difference(self, other):
        return self - other

    def __sub__(self, other):
        new = self.copy()
        new -= other
        return new

    def symmetric_difference(self, other):
        return self ^ other

    def __xor__(self, other):
        new = self.copy()
        new ^= other
        return new

    def copy(self):
        return set(self)

    def update(self, other):
        for item in other:
            self.add(item)

    def __ior__(self, other):
        self.update(other)
        return self

    def intersection_update(self, other):
        for item in self:
            if item not in other:
                self.remove(item)

    def __iand__(self, other):
        self.intersection_update(other)
        return self

    def difference_update(self, other):
        for item in other:
            if item in self:
                self.remove(item)

    def __isub__(self, other):
        self.difference_update(other)
        return self

    def symmetric_difference_update(self, other):
        for item in other:
            if item in self:
                self.remove(item)
            else:
                self.add(item)

    def __ixor__(self, other):
        self.symmetric_difference_update(other)
        return self

    def discard(self, item):
        try:
            self.remove(item)
        except KeyError:
            pass

    def clear(self):
        for item in list(self):
            self.remove(item)
  "   ˆl–Ým_J	µ7µ …@¹q·®¥1hßÅƒeàÄÃ Ù    # FIXME: this should all be confirmed against what a DTD says
# (probably in a test; this may not match the DTD exactly, but we
# should document just how it differs).

# Data taken from http://www.w3.org/TR/html401/index/elements.html

try:
    frozenset
except NameError:
    from sets import Set as frozenset


empty_tags = frozenset([
    'area', 'base', 'basefont', 'br', 'col', 'frame', 'hr',
    'img', 'input', 'isindex', 'link', 'meta', 'param'])

deprecated_tags = frozenset([
    'applet', 'basefont', 'center', 'dir', 'font', 'isindex',
    'menu', 's', 'strike', 'u'])

# archive actually takes a space-separated list of URIs
link_attrs = frozenset([
    'action', 'archive', 'background', 'cite', 'classid',
    'codebase', 'data', 'href', 'longdesc', 'profile', 'src',
    'usemap',
    # Not standard:
    'dynsrc', 'lowsrc',
    ])

# Not in the HTML 4 spec:
# onerror, onresize
event_attrs = frozenset([
    'onblur', 'onchange', 'onclick', 'ondblclick', 'onerror',
    'onfocus', 'onkeydown', 'onkeypress', 'onkeyup', 'onload',
    'onmousedown', 'onmousemove', 'onmouseout', 'onmouseover',
    'onmouseup', 'onreset', 'onresize', 'onselect', 'onsubmit',
    'onunload',
    ])

safe_attrs = frozenset([
    'abbr', 'accept', 'accept-charset', 'accesskey', 'action', 'align',
    'alt', 'axis', 'border', 'cellpad