module Hashie::Extensions::DeepMerge

def _recursive_merge(hash, other_hash, &block)
  other_hash.each do |k, v|
    hash[k] =
      if hash.key?(k) && hash[k].is_a?(::Hash) && v.is_a?(::Hash)
        _recursive_merge(hash[k], v, &block)
      elsif v.is_a?(::Hash)
        _recursive_merge({}, v, &block)
      elsif hash.key?(k) && block_given?
        yield(k, hash[k], v)
      else
        v.respond_to?(:deep_dup) ? v.deep_dup : v
      end
  end
  hash
end