a = [1, 2, 3]
b = a
a[2] = 10
print(a, b)

a = [1,2,3]
b = a.copy()
a[2] = 10
print(a, b)

a = [1,2,3]
b = a[:] # can also be a[0:] or a[:3] or a[0:3]
a[2] = 10
print(a, b)

a = (1, 2, 3)
b = a
a[2] = 10  # Error!
print(a, b)