code: def build_map(function: Callable[[Any], Any] = None,
                unpack: bool = False):
      
      def _build_map(function: Callable[[Any], Any]):
          @wraps(function)
          def _wrapper(*args, **kwargs) -> Map:
              if 'unpack' in kwargs:
                  raise TypeError('"unpack" has to be defined by decorator')
              return Map(function, *args, unpack=unpack, **kwargs)
          return _wrapper
  
      if function:
          return _build_map(function)
  
      return _build_map
docs: Decorator to wrap a function to return a Map operator.
  
      :param function: function to be wrapped
      :param unpack: value from emits will be unpacked (*value)