in python code

Write a function oneSum which takes one input, n, and finds the sum: 1+11+111+1111 +... up to n digits of 1. For example >print (oneSum( 1)) Which is 1-1 >print (oneSum( 2)) 12 Which is 1+11 12. >print (oneSum( 3)) 123 Which is 1+11+111 123. Hint: think about each element of the sum (1, 11, 111, for example) represented as a sum of powers of 10: 111-10A0+104110A2-1+10+100