# File lib/declarative_authorization/authorization.rb, line 552
    def deep_hash_clone (hash)
      hash.inject({}) do |memo, (key, val)|
        memo[key] = case val
                    when Hash
                      deep_hash_clone(val)
                    when NilClass, Symbol
                      val
                    else
                      val.clone
                    end
        memo
      end
    end