deep_merge (ActiveSupport::CoreExtensions::Hash::DeepMerge)

    # File lib/active_support/core_ext/hash/deep_merge.rb, line 7
            def deep_merge(other_hash)
              self.merge(other_hash) do |key, oldval, newval|
                oldval = oldval.to_hash if oldval.respond_to?(:to_hash)
                newval = newval.to_hash if newval.respond_to?(:to_hash)
                oldval.class.to_s == 'Hash' && newval.class.to_s == 'Hash' ? oldval.deep_merge(newval) : newval
              end
            end