MNT: Drop invalid "is not" usage

Author: effigies

nipype/interfaces/afni/base.py

@@ -98,7 +98,7 @@ def standard_image(img_name):
             resource_monitor=False,
             terminal_output="allatonce",
         ).run()
-        if clout.runtime.returncode is not 0:
+        if clout.runtime.returncode != 0:
             return None
 
         out = clout.runtime.stdout

nipype/interfaces/diffusion_toolkit/base.py

@@ -47,7 +47,7 @@ def version():
         """
         clout = CommandLine(command="dti_recon", terminal_output="allatonce").run()
 
-        if clout.runtime.returncode is not 0:
+        if clout.runtime.returncode != 0:
             return None
 
         dtirecon = clout.runtime.stdout

nipype/utils/tests/test_filemanip.py

@@ -154,7 +154,7 @@ def test_copyfiles(_temp_analyze_files, _temp_analyze_files_prime):
 
 
 def test_linkchain(_temp_analyze_files):
-    if os.name is not "posix":
+    if os.name != "posix":
         return
     orig_img, orig_hdr = _temp_analyze_files
     pth, fname = os.path.split(orig_img)
@@ -230,7 +230,7 @@ def test_recopy(_temp_analyze_files):
 
 
 def test_copyfallback(_temp_analyze_files):
-    if os.name is not "posix":
+    if os.name != "posix":
         return
     orig_img, orig_hdr = _temp_analyze_files
     pth, imgname = os.path.split(orig_img)