code: def every(self, step, offset=0):
          
          new = []
  
          for position, item in enumerate(self.items):
              if position % step == offset:
                  new.append(item)
  
          return self.__class__(new)
docs: Create a new collection consisting of every n-th element.
  
          :param step: The step size
          :type step: int
  
          :param offset: The start offset
          :type offset: int
  
          :rtype: Collection