cleanup

data/decision_tree/10_tree.dot

data/decision_tree/10_tree.png

data/decision_tree/1_tree.dot

data/decision_tree/1_tree.png

data/decision_tree/2_tree.dot

data/decision_tree/2_tree.png

data/decision_tree/3_tree.dot

data/decision_tree/3_tree.png

data/decision_tree/4_tree.dot

data/decision_tree/4_tree.png

data/decision_tree/5_tree.dot

data/decision_tree/5_tree.png

data/decision_tree/6_tree.dot

data/decision_tree/6_tree.png

data/decision_tree/7_tree.dot

data/decision_tree/7_tree.png

data/decision_tree/8_tree.dot

data/decision_tree/8_tree.png

data/decision_tree/9_tree.dot

data/decision_tree/9_tree.png