[Zope] Call python functhion in dtml-file

[Serg]

I have problem with below code:
------A.py------
def aaa(self):
    " "
    # do something
class A:
     manage_AAAForm2=DTMLFile('dtml\manage_AAAForm2',globals())
     def aa(self, sub):
     " "
           if sub=='edit':
                return self.manage_AAAForm2(self,self.REQUEST)

-----file A.dtml----
<form name="form" action="aaa">
  <input type="text" name="Name" value=<dtml-var Name>>
  <input type="submit" name=sub value="edit">
</form>

Zope write:
Site Error
An error was encountered while publishing this resource. 
Debugging Notice
Zope has encountered a problem publishing your object. 
Cannot locate object at: http://localhost:8080/min/1/aaa

Zope cannot find function aaa() from A.py.

How can I call python functhion in dtml-file?

Regard,
Serg