'Replaces class="foo bar" with class=["foo", "bar"]
Modifies its input in place.'

def _replace_cdata_list_attribute_values(self, tag_name, attrs):

    if (not attrs):
        return attrs
    if self.cdata_list_attributes:
        universal = self.cdata_list_attributes.get('*', [])
        tag_specific = self.cdata_list_attributes.get(tag_name.lower(), None)
        for attr in attrs.keys():
            if ((attr in universal) or (tag_specific and (attr in tag_specific))):
                value = attrs[attr]
                if isinstance(value, basestring):
                    values = whitespace_re.split(value)
                else:
                    values = value
                attrs[attr] = values
    return attrs
