code: def register_vcs_handler(vcs, method):  # tyoe: (str, str) -> typing.Callable  # decorator
      
      def decorate(f):
          """Store f in HANDLERS[vcs][method]."""
          if vcs not in HANDLERS:
              HANDLERS[vcs] = {}
          HANDLERS[vcs][method] = f
          return f
      return decorate
docs: Decorator to mark a method as the handler for a particular VCS.