message: Update baseball-game.py
diff: # Time: O(n)
  # Space: O(n)
  +# You're now a baseball game point recorder.
  +# Given a list of strings, each string can be one of the 4 following types:
  +#
  +# 1. Integer (one round's score): Directly represents the number of points you get in this round.
  +# 2. "+" (one round's score): Represents that the points you get in this round are
  +# the sum of the last two valid round's points.
  +# 3. "D" (one round's score): Represents that the points you get in this round are
  +# the doubled data of the last valid round's points.
  +# 4. "C" (an operation, which isn't a round's score): Represents the last valid round's points
  +# you get were invalid and should be removed.
  +#
  +# Each round's operation is permanent and could have an impact on the round before and the round after.
  +# You need to return the sum of the points you could get in all the rounds.
  +#
  +# Example 1:
  +#
  +# Input: ["5","2","C","D","+"]
  +# Output: 30
  +# Explanation:
  +# Round 1: You could get 5 points. The sum is: 5.
  +# Round 2: You could get 2 points. The sum is: 7.
  +# Operation 1: The round 2's data was invalid. The sum is: 5.
  +# Round 3: You could get 10 points (the round 2's data has been removed). The sum is: 15.
  +# Round 4: You could get 5 + 10 = 15 points. The sum is: 30.
  +#
  +# Example 2:
  +#
  +# Input: ["5","-2","4","C","D","9","+","+"]
  +# Output: 27
  +# Explanation:
  +# Round 1: You could get 5 points. The sum is: 5.
  +# Round 2: You could get -2 points. The sum is: 3.
  +# Round 3: You could get 4 points. The sum is: 7.
  +# Operation 1: The round 3's data is invalid. The sum is: 3.
  +# Round 4: You could get -4 points (the round 3's data has been removed). The sum is: -1.
  +# Round 5: You could get 9 points. The sum is: 8.
  +# Round 6: You could get -4 + 9 = 5 points. The sum is 13.
  +# Round 7: You could get 9 + 5 = 14 points. The sum is 27.
  +#
  +# Note:
  +# The size of the input list will be between 1 and 1000.
  +# Every integer represented in the list will be between -30000 and 30000.
  +
  class Solution(object):
  def calPoints(self, ops):
  """
  