code: def open(self):
          
          if self._f is not None:
              return self._f
          try:
              rv, self.should_close = open_stream(self.name, self.mode,
                                                  self.encoding,
                                                  self.errors,
                                                  atomic=self.atomic)
          except (IOError, OSError) as e:
              from .exceptions import FileError
              raise FileError(self.name, hint=get_streerror(e))
          self._f = rv
          return rv
docs: Opens the file if it's not yet open.  This call might fail with
          a :exc:`FileError`.  Not handling this error will produce an error
          that Click shows.