new_contents: a = dict(A = 1, Z = -1)
  b = {"A": 1, "Z": -1}
  c = dict(zip(["A", "Z"], [1, -1]))
  d = dict([("A", 1), ("Z", -1)])
  e = dict(b)
  
  print(a == b == c == d == e)
  # compare object id
  print(a is b)
  
  lst = list(zip(['h', 'e', 'l', 'l', 'o'], [1, 2, 3, 4, 5]))
  print(lst)
  
  z = zip(["a", "b", "c", "d"], [1, 2, 3])
  z1 = zip(["a", "b"], [1, 2, 3])
  print(list(z))
  print(list(z1))
  
  r = range(6)
  print(list(zip("hell0", r)))
  
  map = {}
  map["name"] = "Scott"
  map["active"] = True
  print(len(map))
  print(map["name"])
  # no-existing entry, runtime error
  # print(map["dummy"])
  print(map)
  del map["active"]
  print(map)
  
  # key existing check
  print("salary" in map)
  print("name" in map)
  
  print(map.keys())
  print(map.values())
  print(map.items())
  
  print("Scott" in map.values())
  
  map = {"e": 1, "h": 0, "o": 4, "1": 3, "x": 4}
  
  print(map.popitem())
  print(map.popitem())
  print(map.popitem())
  print(map.popitem())
  print(map)
  
  map = {"e": 1, "h": -99, "o": 4, "1": 3, "x": 4}
  print(map.pop("h"))
  del map["e"]
  print(map)
  
  default = map.pop("dummy-key", 1000)
  print(default)
  
  print(map.get("abc"))
  
  
  d = {}
  d.setdefault("a", 1)
  print(d)
  d.setdefault("a", 5)
  print(d)
subject: Add mapping type demo.