Merge pull request #493 from jamesmartini/develop_py38syntax

Explored SyntaxWarnings associated to using py38

src/cogent3/core/tree.py

@@ -1225,7 +1225,7 @@ def _get_sub_tree(
                         for (n, v) in list(self.params.items())
                         if v is not None
                         and child.params.get(n) is not None
-                        and n is not "length"
+                        and n != "length"
                     ]
                     length = self.length + child.length
                     if length:

src/cogent3/util/parallel.py

@@ -52,7 +52,7 @@ def get_rank():
         rank = COMM.Get_rank()
     else:
         process_name = multiprocessing.current_process().name
-        if process_name is not "MainProcess":
+        if process_name != "MainProcess":
             rank = int(process_name.split("-")[-1])
     return rank
 

tests/test_maths/test_stats/test_jackknife.py

@@ -21,7 +21,7 @@ def pmcc(data, axis=1):
     is two dimensional: [[Y1], [Y2]] (trying to determine the correlation
     coefficient between data sets Y1 and Y2"""
 
-    if axis is 0:
+    if axis == 0:
         data = data.transpose()
         axis = 1
 
@@ -96,7 +96,7 @@ def test_jackknife_stats(self):
         test_knife = JackknifeStats(data.shape[1], pmcc_stat)
         self.assertFloatEqual(test_knife.JackknifedStat, 1.2905845)
         self.assertFloatEqual(test_knife.Exception, 0.2884490)
-        self.assertTrue(test_knife._jackknifed_stat is not None)
+        self.assertTrue(test_knife._jackknifed_stat != None)
 
         # Vector
         mean_stat = stat_maker(mean, data, 1)