functions = {(None, 'boolean'): <function Boolean>, (None, 'ceiling'): <function Ceiling>, (None, 'concat'): <function Concat>, (None, 'contains'): <function Contains>, (None, 'count'): <function Count>, (None, 'current'): <function Current>, (None, 'document'): <function Document>, (None, 'element-available'): <function ElementAvailable>, (None, 'false'): <function False>, (None, 'floor'): <function Floor>, ...}