docs: def index(self, element: Element) -> int:
          """
          Return the index in the array of the first item whose value is element.
          It is an error if there is no such item.
  
          >>> element = String('hello')
          >>> array = Array(content=[element])
          >>> array.index(element)
          0
          """
  
          from refract.refraction import refract
          return self.content.index(refract(element))