dp3.py

from copy import deepcopy
x=[1,2,[3,4]]
#deepcopying x
y=deepcopy(x)

#Modifying elements in the outer list.
#It is not reflected in the copied list.
x[0]=99
print (x)#Output:[99, 2, [3, 4]]
print (y)#Output:[1, 2, [3, 4]]