Hash#path_exists?(*path) method for check paths in hash

hash_extension.rb

class Hash

  def path_exists?(*path)
    path.flatten.each do |key|
      if key.instance_of? Hash
        return false unless self[key.keys.first]
        return false unless self[key.keys.first].path_exists?(key.values)
      elsif key.instance_of? Array
        return self.path_exists?(key)
      else
        return false if self.respond_to?(:keys) && self[key].nil?
      end
    end

    return true
  end

end

Example:
hash = {:user => {:old_password => 1, :new_password => '2'}}

hash.path_exists?(:user) #true
hash.path_exists?({:user => [:old_password, :new_password]}) #true
hash.path_exists?({:user => [:old_password]}) #true
hash.path_exists?({:user => [:old_password, :new_password]}, :profile) #false
hash.path_exists?({:people => [:old_password, :new_password]}) #false
hash.path_exists?({:user => [:password]}) #false
hash.path_exists?([:password]) #false