code: def collection_index(self):
          
  
          indexes = self.options.index
          #add current directory to indexes
          indexes.insert(0, os.getcwd())
          if 'IDO_INDEXES' in os.environ:
              indexes.extend(os.environ['IDO_INDEXES'].split(';'))
  
          indexes.append(os.path.join(os.path.dirname(__file__), 'packages').replace('\\', '/'))
          return indexes
docs: Collection index link to self.indexes, the order should be:
          1. command argument
          2. environment
          3. default packages directory