'Handles FunctionDef node and set context.'

def visit_FunctionDef(self, node):

    if (self.current_function is None):
        self.add_entry(node.name)
        self.context.append(node.name)
        self.current_function = node
        for child in node.body:
            self.visit(child)
        self.context.pop()
        self.current_function = None
