81c81
< for node_index in xrange(len(nodes)):
---
> for node_index in range(len(nodes)):
113,114c113,114
< for row in xrange(num_rows):
< for col in xrange(num_columns):
---
> for row in range(num_rows):
> for col in range(num_columns):
128,129c128,129
< for row in xrange(num_rows):
< for col in xrange(num_columns):
---
> for row in range(num_rows):
> for col in range(num_columns):
143,144c143,144
< for col in xrange(num_columns):
< for row in xrange(num_rows):
---
> for col in range(num_columns):
> for row in range(num_rows):
158,159c158,159
< for col in xrange(num_columns):
< for row in xrange(num_rows):
---
> for col in range(num_columns):
> for row in range(num_rows):