https://medium.com/broken-window/many-names-one-memory-address-122f78734cb6
https://stackoverflow.com/questions/725782/in-python-what-is-the-difference-between-append-and
+=
__iadd__()
>>> my_list = [1, 2, 3]
>>> id(my_list)
140418271352128
>>> another_list = my_list
>>> id(another_list)
140418271352128
>>> another_list += [4,]
>>> id(another_list)
140418271352128
>>> print(another_list)
[1, 2, 3, 4]
>>> print(my_list)
[1, 2, 3, 4]= +
__add__()
This function returns a new copy instead of modifying the list in place.
>>> my_list = [1, 2, 3]
>>> id(my_list)
140418271454720
>>> another_list = my_list
>>> id(another_list)
140418271454720
>>> another_list = another_list + [4,]
>>> id(another_list)
140418271504832
>>> print(another_list)
[1, 2, 3, 4]
>>> print(my_list)
[1, 2, 3]append()
>>> my_list = [1, 2, 3]
>>> id(my_list)
140418271352128
>>> another_list = my_list
>>> id(another_list)
140418271352128
>>> another_list.append(4)
>>> id(another_list)
140418271352128
>>> print(another_list)
[1, 2, 3, 4]
>>> print(my_list)
[1, 2, 3, 4]extend()
>>> my_list = [1, 2, 3]
>>> id(my_list)
140418271504832
>>> another_list = my_list
>>> id(another_list)
140418271504832
>>> another_list.extend([4])
>>> id(another_list)
140418271504832
>>> print(another_list)
[1, 2, 3, 4]
>>> print(my_list)
[1, 2, 3, 4]