85c85
< for node_index in xrange(len(nodes)):
---
> for node_index in range(len(nodes)):
117,118c117,118
< for row in xrange(num_rows):
< for col in xrange(num_columns):
---
> for row in range(num_rows):
> for col in range(num_columns):
130,131c130,131
< for row in xrange(num_rows):
< for col in xrange(num_columns):
---
> for row in range(num_rows):
> for col in range(num_columns):
144,145c144,145
< for col in xrange(num_columns):
< for row in xrange(num_rows):
---
> for col in range(num_columns):
> for row in range(num_rows):
157,158c157,158
< for col in xrange(num_columns):
< for row in xrange(num_rows):
---
> for col in range(num_columns):
> for row in range(num_rows):