def module_include(base, mod)
      old_methods = {}

      mod.instance_methods.each do |sym|
        old_methods[sym] = base.instance_method(sym) if base.method_defined?(sym)
      end

      mod.instance_methods.each do |sym|
        method = mod.instance_method(sym)
        base.send(:define_method, sym, method)
      end

      yield
    ensure
      mod.instance_methods.each do |sym|
        base.send(:undef_method, sym) if base.method_defined?(sym)
      end
      old_methods.each do |sym, method|
        base.send(:define_method, sym, method)
      end
    end
def module_include(base, mod)
      old_methods = {}

      mod.instance_methods.each do |sym|
        old_methods[sym] = base.instance_method(sym) if base.method_defined?(sym)
      end

      mod.instance_methods.each do |sym|
        method = mod.instance_method(sym)
        base.send(:define_method, sym, method)
      end

      yield
    ensure
      mod.instance_methods.each do |sym|
        base.send(:undef_method, sym) if base.method_defined?(sym)
      end
      old_methods.each do |sym, method|
        base.send(:define_method, sym, method)
      end
    end
Internal: Inject into target module for the duration of the block.

 mod - Module

 Returns result of block.