# File lib/multimethod/table.rb, line 139
    def lookup_multimethod(name)
      name = name.to_s

      # THREAD CRITICAL BEGIN
      unless mm = @multimethod_by_name[name]
        mm = Multimethod.new(name)
        mm.table = self
        @multimethod_by_name[name] = mm
        @multimethod << mm
      end
      # THREAD CRITICAL END

      mm
    end