code: def unload_plugin(name, category=None):
      
      if category is not None:
          _all_plugins[category].pop(name)
      else:
          for cat in _all_plugins:
              if name in _all_plugins[cat]:
                  _all_plugins[cat].pop(name)
docs: remove single plugin
  
      Parameters
      ----------
      name : str
          plugin name
      category : str
          plugin category
  
      Examples
      --------
  
      >>> from pprint import pprint
      >>> pprint(view_plugins())
      {'decoders': {}, 'encoders': {}, 'parsers': {}}
  
      >>> class DecoderPlugin(object):
      ...     plugin_name = 'example'
      ...     plugin_descript = 'a decoder for dicts containing _example_ key'
      ...     dict_signature = ('_example_',)
      ...
      >>> errors = load_plugin_classes([DecoderPlugin],category='decoders')
  
      >>> pprint(view_plugins())
      {'decoders': {'example': 'a decoder for dicts containing _example_ key'},
       'encoders': {},
       'parsers': {}}
  
      >>> unload_plugin('example','decoders')
      >>> pprint(view_plugins())
      {'decoders': {}, 'encoders': {}, 'parsers': {}}