input: Write a function to translate a given text from English to French using the Googletrans library. The function should take a string as input, translate it to French, and return the translated text. If the input text is empty, the function should return an empty string.
  assert french_translation("Hello, this is a sample text to translate.")=="Bonjour, ceci est un texte d'exemple à traduire."
  assert french_translation("Good morning!")=="Bonjour !"
  assert french_translation("")==""
  assert french_translation("This is a test.")=="Ceci est un test."
  assert french_translation("How are you?")=="Comment ça va ?"
output: def french_translation(text):
      if not text:
          return ""
      from googletrans import Translator
      translator = Translator()
      translation = translator.translate(text, src='en', dest='fr')
      return translation.text