#TODO(aykut)
# -> get rid of parent_id==0 check in AddOrUpdateNode method, when adding edge
# and when setting parent_id attribute
# they are necessary -> line 1120 and line 1121 are unnecessary, since they are already 0.0 and 1.0
#        horizontal_lower_bound[self._root_id] = 0.0
#        horizontal_upper_bound[self._root_id] = 1.0
# -> note that this script file is for python 3 and rest of our code is in 2.7.
# we use this file with 2.7, be carefull, especially integer division
# in python2.7 5/2=2, in python3 5/2=2.5
# -> check subtree_root attribute of node class
# -> fix documentation
# -> remove unncesssary stuff
# -> write help
# -> Change we deal with infinity in BB
# -> in BB root node is 0 and parent of the root node is -1, previous authors
# use 1 as root node and 0 as the parent of root node. Solve this conflict
# using a global variable like DUMMY_NODE.
#

