code: def contains_at(self, x, index):
          
  
          try:
              if is_collection(x):
                  for _x in x:
                      if (_x in self.all[index]) or (_x == self.all[index]):
                          return True
                      else:
                          return False
              else:
                  return (x in self.all[index])
  
          except IndexError:
              return False
docs: Tests if given [list of] string is at given index.