input: Write a function to calculate the maximum possible revenue from the items with given weights and values. The function should return the maximum value that can be obtained with a given maximum capacity W.
  assert knapsack([2, 1, 3], [4, 2, 3], 3) == 7
  assert knapsack([1, 2, 3], [6, 10, 12], 3) == 22
  assert knapsack([1, 1, 1], [10, 20, 30], 2) == 50
  assert knapsack([1, 2, 3], [1, 2, 3], 0) == 0
  assert knapsack([10], [100], 1) == 100
output: def knapsack(weights, values, W):
      n = len(weights)
      dp = [[0] * (W + 1) for _ in range(n + 1)]
      
      for i in range(1, n + 1):
          for w in range(W + 1):
              if weights[i - 1] <= w:
                  dp[i][w] = max(dp[i - 1][w], dp[i - 1][w - weights[i - 1]] + values[i - 1])
              else:
                  dp[i][w] = dp[i - 1][w]
      
      return dp[n][W]