# File lib/backports/2.5.0/enumerable/one.rb, line 8
    def one_with_pattern?(pattern = Backports::Undefined, &block)
      return one_without_pattern?(&block) if Backports::Undefined == pattern
      found_one = false
      each_entry do |o|
        if pattern === o
          return false if found_one
          found_one = true
        end
      end
      found_one
    end