code: def ticks_difference(price_1, price_2):
      
      price_1_index = PRICES.index(as_dec(price_1))
      price_2_index = PRICES.index(as_dec(price_2))
      return abs(price_1_index - price_2_index)
docs: Returns the absolute difference in terms of "ticks" (i.e. individual
      price increments) between two Betfair prices.
  
      :param float price_1: An exact, valid Betfair price
      :param float price_2: An exact, valid Betfair price
      :returns: The absolute value of the difference between the prices in "ticks"
      :rtype: int