docs: def register(self, value):
          """ Register function to globals. """
          if self.env is None:
              raise PluginException('The plugin must be installed to application.')
  
          def wrapper(func):
              name = func.__name__
              if isinstance(value, str):
                  name = value
              if callable(func):
                  self.env.globals[name] = func
              return func
  
          if callable(value):
              return wrapper(value)
  
          return wrapper