@daniel-s-ingram Similar changes needed on Problems 25 and 28 so they can run on Python 3.
flake8 testing of https://github.com/TheAlgorithms/Python on Python 3.6.3
$ __flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics__
```
./Project Euler/Problem 10/sol1.py:5:11: F821 undefined name 'xrange'
for i in xrange(2, int(sqrt(n))+1):
^
./Project Euler/Problem 10/sol1.py:17:11: F821 undefined name 'xrange'
for i in xrange(3, n, 2):
^
./Project Euler/Problem 25/sol1.py:10:12: F821 undefined name 'xrange'
for i in xrange(2, n+1):
^
./Project Euler/Problem 28/sol1.py:7:11: F821 undefined name 'xrange'
for i in xrange(1, int(ceil(n/2.0))):
^
4 F821 undefined name 'xrange'
```
