code: def gen_source(self, ast, name, customize, is_lambda=False, returnNone=False):
          
  
          rn = self.return_none
          self.return_none = returnNone
          old_name = self.name
          self.name = name
          # if code would be empty, append 'pass'
          if len(ast) == 0:
              self.println(self.indent, 'pass')
          else:
              self.customize(customize)
              if is_lambda:
                  self.write(self.traverse(ast, is_lambda=is_lambda))
              else:
                  self.text = self.traverse(ast, is_lambda=is_lambda)
                  self.println(self.text)
          self.name = old_name
          self.return_none = rn
docs: convert SyntaxTree to Python source code