How to use the saspy.sastabulate.TabulationItem function in saspy

code = self.key
        if self.label != None:
            code += "='%s'" % self.label
        if self.all:
            code = "(%s ALL='%s')" % (code, self.all)
        if self.child:
            code += " * %s" % str(self.child)
        return code

    def _gather(self, collected):
        collected['classes'].add(self.key)
        if (self.child):
            self.child._gather(collected)


class Var(TabulationItem):
    def __str__(self):
        code = self.key
        if self.label != None:
            code += "='%s'" % self.label
        if self.child:
            code += " * %s" % str(self.child)
        return code

    def __mul__(self, other):
        if isinstance(other, Class):
            raise SyntaxError('A Class variable cannot be a descendent of a Var')
        return super().__mul__(other)

    def _gather(self, collected):
        collected['vars'].add(self.key)
        if (self.child):

return other.add(self, True)

    def __mul__(self, other):
        if self.child:
            self.child = self.child.__mul__(other)
        else:
            # always clone for composition purposes
            return self.with_(child=other)
        return self

    # override for entities needing to add top-level entries
    def _gather(self, collected):
        pass


class Class(TabulationItem):
    def __init__(self, key, **kwargs):
        super().__init__(key, **kwargs)
        self.all = kwargs.get('all', None)
        self._kwargs += ['all']

    def __str__(self):
        code = self.key
        if self.label != None:
            code += "='%s'" % self.label
        if self.all:
            code = "(%s ALL='%s')" % (code, self.all)
        if self.child:
            code += " * %s" % str(self.child)
        return code

    def _gather(self, collected):

if self.child:
            code += " * %s" % str(self.child)
        return code

    def __mul__(self, other):
        if isinstance(other, Class):
            raise SyntaxError('A Class variable cannot be a descendent of a Var')
        return super().__mul__(other)

    def _gather(self, collected):
        collected['vars'].add(self.key)
        if (self.child):
            self.child._gather(collected)


class Statistic(TabulationItem):
    def __init__(self, key, **kwargs):
        super().__init__(key, **kwargs)
        self.format = kwargs.get('format', None)
        self._kwargs += ['format']

    def __str__(self):
        code = self.key
        if self.label != None:
            code += "='%s'" % self.label
        if self.format:
            code += "*f=%s" % self.format
        return code

    def __mul__(self, other):
        raise SyntaxError("Statistics cannot have further descendents")

def __or__(self, other):
        if isinstance(other, TabulationItem):
            return Grouping([self, other])
        if type(other) == Grouping:
            return other.add(self, True)