add yapf style and apply yapf to format all Python files

This recreates pull request #2192

examples/pybullet/gym/pybullet_envs/deep_mimic/learning/path.py

@@ -1,46 +1,47 @@
 import numpy as np
 from pybullet_envs.deep_mimic.env.env import Env
 
+
 class Path(object):
-    def __init__(self):
-        self.clear()
-        return
 
-    def pathlength(self):
-        return len(self.actions)
+  def __init__(self):
+    self.clear()
+    return
 
-    def is_valid(self):
-        valid = True
-        l = self.pathlength()
-        valid &= len(self.states) == l + 1
-        valid &= len(self.goals) == l + 1
-        valid &= len(self.actions) == l
-        valid &= len(self.logps) == l
-        valid &= len(self.rewards) == l
-        valid &= len(self.flags) == l
+  def pathlength(self):
+    return len(self.actions)
 
-        return valid
+  def is_valid(self):
+    valid = True
+    l = self.pathlength()
+    valid &= len(self.states) == l + 1
+    valid &= len(self.goals) == l + 1
+    valid &= len(self.actions) == l
+    valid &= len(self.logps) == l
+    valid &= len(self.rewards) == l
+    valid &= len(self.flags) == l
 
-    def check_vals(self):
-        for vals in [self.states, self.goals, self.actions, self.logps,
-                  self.rewards]:
-            for v in vals:
-                if not np.isfinite(v).all():
-                    return False
-        return True
+    return valid
 
-    def clear(self):
-        self.states = []
-        self.goals = []
-        self.actions = []
-        self.logps = []
-        self.rewards = []
-        self.flags = []
-        self.terminate = Env.Terminate.Null
-        return
+  def check_vals(self):
+    for vals in [self.states, self.goals, self.actions, self.logps, self.rewards]:
+      for v in vals:
+        if not np.isfinite(v).all():
+          return False
+    return True
 
-    def get_pathlen(self):
-        return len(self.rewards)
+  def clear(self):
+    self.states = []
+    self.goals = []
+    self.actions = []
+    self.logps = []
+    self.rewards = []
+    self.flags = []
+    self.terminate = Env.Terminate.Null
+    return
 
-    def calc_return(self):
-        return sum(self.rewards)
+  def get_pathlen(self):
+    return len(self.rewards)
+
+  def calc_return(self):
+    return sum(self.rewards)