code: def visit_FunctionDef(self, node):
          
          # Ensure there are no nested functions.
          assert self.current_function is None
          self.current_function = node
          self.naming = dict()
          self.in_cond = False  # True when we are in a if, while or for
          self.generic_visit(node)
          self.current_function = None
docs: Initialize variable for the current function to add edges from calls.
  
          We compute variable to call dependencies and add edges when returns
          are reach.