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Initializing a list as blank is the most memory efficient way of doing it - Python Interesting Fact

Initializing list in Python as blank is the most memory efficient way of doing it. Logically this won't make sense, but the program below will prove.
from sys import getsizeof

print('declare a with one element and get size of x')
x = []
print(x)
print(getsizeof(x))

print('declare a with one element and get size of a')
a = ['a']
print(a)
print(getsizeof(a))

print('declare b with two elements and get size of b')
b = ['a','b']
print(b)
print(getsizeof(b))

print('declare c with two elements and get size of c')
c = ['a', 'b', 'c']
print(c)
print(getsizeof(c))

print('append one element and see size of')
x.append('a')
print(x)
print(getsizeof(x))
a.append('b')
print(a)
print(getsizeof(a))
b.append('c')
print(b)
print(getsizeof(b))

print('append another element-list and see size of')
x.append(['b', 'c'])
print(x)
print(getsizeof(x))
a.append(['c', 'd'])
print(a)
print(getsizeof(a))
b.append(['e', 'f'])
print(b)
print(getsizeof(b))

print('append another grouo of elements and see size of')
x.extend(['d', 'e'])
print(x)
print(getsizeof(x))
a.extend(['e', 'f'])
print(a)
print(getsizeof(a))
b.extend(['g', 'h'])
print(b)
print(getsizeof(b))
Output:
declare a with one element and get size of x
[]
64
declare a with one element and get size of a
['a']
72
declare b with two elements and get size of b
['a', 'b']
80
declare c with two elements and get size of c
['a', 'b', 'c']
88
append one element and see size of
['a']
96
['a', 'b']
104
['a', 'b', 'c']
112
append another element-list and see size of
['a', ['b', 'c']]
96
['a', 'b', ['c', 'd']]
104
['a', 'b', 'c', ['e', 'f']]
112
append another grouo of elements and see size of
['a', ['b', 'c'], 'd', 'e']
96
['a', 'b', ['c', 'd'], 'e', 'f']
104
['a', 'b', 'c', ['e', 'f'], 'g', 'h']
112

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