old_contents: from importlib import import_module
  
  _modules = ['branching', 'data_processing']
  
  class Execute(object):
      def __init__(self, registers, process_mode, memory):
          self.instruction = {}
  
          for module_name in _modules:
              mod = import_module("Execute." + module_name)
              for cls in [obj for obj in mod.__dict__ if type(mod.__dict__[obj]) == type]:
                  cls_instance = mod.__dict__[cls](registers, process_mode, memory)
                  for cls_instr in [func for func in mod.__dict__[cls].__dict__ if '_' not in func]:
                      self.instruction[cls_instr] = cls_instance[cls_instr]
  
      def __call__(self, args):
          try:
              self.instruction[args['instr']](args)
          except (KeyError, NotImplementedError):
              print('unhandled: %s - %s' % (args['instr'], args['encoding']))
new_contents: from importlib import import_module
  
  _modules = ['branching', 'data_processing']
  
  class Execute(object):
      def __init__(self, registers, process_mode, memory):
          self.instruction = {}
  
          for module_name in _modules:
              mod = import_module("Execute." + module_name)
              for cls in [obj for obj in mod.__dict__ if type(mod.__dict__[obj]) == type]:
                  cls_instance = mod.__dict__[cls](registers, process_mode, memory)
                  for cls_instr in [func for func in mod.__dict__[cls].__dict__ if not func.startswith('_')]:
                      try:
                          self.instruction[cls_instr]
                      except KeyError:
                          self.instruction[cls_instr] = cls_instance[cls_instr]
                      else:
                          raise Warning('Multiple instruction handlers detected for "%s"' % cls_instr)
  
      def __call__(self, args):
          try:
              self.instruction[args['instr']](args)
          except (KeyError, NotImplementedError):
              print('unhandled: %s - %s' % (args['instr'], args['encoding']))
subject: Check for duplicate instruction handlers