code: def register_module(self, module, idx=-1):
          
  
          if module in self._modules:
              raise AlreadyRegisteredError("Module '{0}' is already registered on loader.".format(module))
  
          if idx < 0:
              self._modules.append(module)
          else:
              self._modules.insert(idx, module)
docs: Register a module. You could indicate position inside inner list.
  
          :param module: must be a string or a module object to register.
          :type module: str
          :param idx: position where you want to insert new module. By default it is inserted at the end.
          :type idx: int