code: def countOf(a, b):
      "Return the number of times b occurs in a."
      count = 0
      for i in a:
          if i == b:
              count += 1
      return counf countOf(a, b):
      "Return the number of times b occurs in a."
      count = 0
      for i in a:
          if i == b:
              count += 1
      return count
docs: Return the number of times b occurs in a.