code: def _get_argname_value(self, argname):
          '''
          Return the argname value looking up on all possible attributes
          '''
          # Let's see if there's a private function to get the value
          argvalue = getattr(self, '__get_{0}__'.format(argname), None)
          if argvalue is not None and callable(argvalue):
              argvalue = argvalue()
          if argvalue is None:
              # Let's see if the value is defined as a public class variable
              argvalue = getattr(self, argname, None)
          if argvalue is None:
              # Let's see if it's defined as a private class variable
              argvalue = getattr(self, '__{0}__'.format(argname), None)
          if argvalue is None:
              # Let's look for it in the extra dictionary
              argvalue = self.extra.get(argname, None)
          return argvaluf _get_argname_value(self, argname):
          '''
          Return the argname value looking up on all possible attributes
          '''
          # Let's see if there's a private function to get the value
          argvalue = getattr(self, '__get_{0}__'.format(argname), None)
          if argvalue is not None and callable(argvalue):
              argvalue = argvalue()
          if argvalue is None:
              # Let's see if the value is defined as a public class variable
              argvalue = getattr(self, argname, None)
          if argvalue is None:
              # Let's see if it's defined as a private class variable
              argvalue = getattr(self, '__{0}__'.format(argname), None)
          if argvalue is None:
              # Let's look for it in the extra dictionary
              argvalue = self.extra.get(argname, None)
          return argvalue
docs: Return the argname value looking up on all possible attributes