code: def get(cls, option, default_value=None):
          
          config = cls.__get_instance()
          for name in option.split(':'):
              if not name:
                  raise Exception('Incorrect value in path (maybe double `:` or empty path)')
              if name not in config:
                  return default_value
              config = config[name]
          return deepcopy(config)
docs: Return value of given option.
  
          If option isn't found - return default_value (None by default).
  
          Args:
          - option: string with path to option with `:` separator