How to use the chameleon.core.types.escape function in Chameleon

if parent is not None and parent.strip_text and parent[-1] is self.element:
                        tail = tail.rstrip('\n ')

                parent = self.element.getparent()
                if parent is not None and not parent.node._interpolation_enabled:
                    return (tail,)

                parts = self.element.translator.split(tail)
                if self.element.tag == '{http://www.w3.org/1999/xhtml}cdata':
                    return parts

                if not self._interpolation_escape:
                    return parts

                return tuple(
                    isinstance(part, types.expression) and types.escape(part) or \
                    self.element.meta_structure is True and part or \
                    utils.htmlescape(part) for part in parts)

            return ()

if parent is not None and parent.strip_text and parent[-1] is self.element:
                        tail = tail.rstrip('\n ')

                parent = self.element.getparent()
                if parent is not None and not parent.node._interpolation_enabled:
                    return (tail,)

                parts = self.element.translator.split(tail)
                if self.element.tag == '{http://www.w3.org/1999/xhtml}cdata':
                    return parts

                if not self._interpolation_escape:
                    return parts

                return tuple(
                    isinstance(part, types.expression) and types.escape(part) or \
                    self.element.meta_structure is True and part or \
                    utils.htmlescape(part) for part in parts)

            return ()

parent = self.element.getparent()
                if parent is not None and self.element.strip_text and parent[0] is self.element:
                    text = text.lstrip('\n ')

                if not self._interpolation_enabled:
                    return (text,)

                parts = self.element.translator.split(text)
                if self.element.tag == '{http://www.w3.org/1999/xhtml}cdata':
                    return parts

                if not self._interpolation_escape:
                    return parts

                return tuple(
                    isinstance(part, types.expression) and types.escape(part) or \
                    self.element.meta_structure is True and part or \
                    utils.htmlescape(part) for part in parts)

            return ()

parent = self.element.getparent()
                if parent is not None and self.element.strip_text and parent[0] is self.element:
                    text = text.lstrip('\n ')

                if not self._interpolation_enabled:
                    return (text,)

                parts = self.element.translator.split(text)
                if self.element.tag == '{http://www.w3.org/1999/xhtml}cdata':
                    return parts

                if not self._interpolation_escape:
                    return parts

                return tuple(
                    isinstance(part, types.expression) and types.escape(part) or \
                    self.element.meta_structure is True and part or \
                    utils.htmlescape(part) for part in parts)

            return ()

>>> output("structure context/title")
        value('context/title')        

        >>> output(" structure context/title")
        value('context/title')

        """

        string = string.lstrip(' ')
        if string.startswith('structure '):
            return self.tales(string[len('structure'):])
        
        expression = self.tales(string)

        if isinstance(expression, types.parts):
            return types.escape(expression)

        return types.escape((expression,))

def __init__(self, value, defer=False):
        self.assign = Assign(value)
        self.structure = not isinstance(value, types.escape)
        self.defer = defer

>>> output("context/title")
        escape(value('context/title'),)

        >>> output("structure context/title")
        value('context/title')        
        """
        
        if string.startswith('structure '):
            return self.expression(string[len('structure')+1:])
        
        expression = self.expression(string)

        if isinstance(expression, types.parts):
            return types.escape(expression)

        return types.escape((expression,))

>>> output = MockExpressionTranslator().output

        >>> output("context/title")
        escape(value('context/title'),)

        >>> output("structure context/title")
        value('context/title')        
        """
        
        if string.startswith('structure '):
            return self.expression(string[len('structure')+1:])
        
        expression = self.expression(string)

        if isinstance(expression, types.parts):
            return types.escape(expression)

        return types.escape((expression,))

>>> output(" structure context/title")
        value('context/title')

        """

        string = string.lstrip(' ')
        if string.startswith('structure '):
            return self.tales(string[len('structure'):])
        
        expression = self.tales(string)

        if isinstance(expression, types.parts):
            return types.escape(expression)

        return types.escape((expression,))