class Hash

def stringify_keys

def stringify_keys
  keys.each do |key|
    self[key.to_s] = delete(key)
  end
  self
end if !{}.respond_to?(:stringify_keys)

def symbolize_keys

def symbolize_keys
  keys.each do |key|
    self[(key.to_sym rescue key) || key] = delete(key)
  end
  self
end if !{}.respond_to?(:symbolize_keys)