new_contents: import copy
  
  a = [1,2,3]
  b = a
  b[1]=22
  print(a)
  print(id(a) == id(b))
  
  # deep copy
  c = copy.deepcopy(a)
  print(id(a) == id(c))
  c[1] = 2
  print(a)
  a[1] = 111
  print(c)
  
  # shallow copy
  a = [1,2,[3,4]]
  d = copy.copy(a)
  print(id(a) == id(d))
  print(id(a[2]) == id(d[2]))
subject: create basic30