Merge #14903: tests: Handle ImportError explicitly, improve comparisons against None

c9ba253f4f5d675d7736d24c1167229d0898ef1a Add E711 to flake8 check (Daniel Ingram)
17b55202dae8d6e21d2490de89b345c55f7694c0 Compare to None with is/is not (Daniel Ingram)
1b89074ae27ce123adbeed57343deaef13c14f81 Change '== None' to 'is None' (Daniel Ingram)
16d293772365d57cc1a279d5ad0fa6f44b12ed54 Handle exception as ImportError (Daniel Ingram)

Pull request description:

Tree-SHA512: aa5875ea3d9ac47ac898545ff023b511042cd377ea0c4594074daae119f3d4f3fc295721aad94a732a907086ecb32bce19a8eed38adf479f12663c4e8944f721

4 files changed, 4 insertions, 4 deletions

diff --git a/contrib/devtools/clang-format-diff.py b/contrib/devtools/clang-format-diff.py
index 77e845a9b4..f322b3a880 100755
--- a/contrib/devtools/clang-format-diff.py
+++ b/contrib/devtools/clang-format-diff.py
@@ -109,7 +109,7 @@ def main():
     match = re.search('^\+\+\+\ (.*?/){%s}(\S*)' % args.p, line)
     if match:
       filename = match.group(2)
-    if filename == None:
+    if filename is None:
       continue
 
     if args.regex is not None:
diff --git a/contrib/devtools/copyright_header.py b/contrib/devtools/copyright_header.py
index 2d539ffe43..6d7a592f01 100755
--- a/contrib/devtools/copyright_header.py
+++ b/contrib/devtools/copyright_header.py
@@ -491,7 +491,7 @@ def get_git_change_year_range(filename):
 
 def file_already_has_core_copyright(file_lines):
     index, _ = get_updatable_copyright_line(file_lines)
-    return index != None
+    return index is not None
 
 ################################################################################
 # insert header execution
diff --git a/contrib/devtools/github-merge.py b/contrib/devtools/github-merge.py
index 4e90f85f50..c7a64bd6f9 100755
--- a/contrib/devtools/github-merge.py
+++ b/contrib/devtools/github-merge.py
@@ -25,7 +25,7 @@ import json
 import codecs
 try:
     from urllib.request import Request,urlopen
-except:
+except ImportError:
     from urllib2 import Request,urlopen
 
 # External tools (can be overridden using environment)
diff --git a/contrib/devtools/update-translations.py b/contrib/devtools/update-translations.py
index f0098cfcdf..1b9d3a4c27 100755
--- a/contrib/devtools/update-translations.py
+++ b/contrib/devtools/update-translations.py
@@ -125,7 +125,7 @@ def escape_cdata(text):
     return text
 
 def contains_bitcoin_addr(text, errors):
-    if text != None and ADDRESS_REGEXP.search(text) != None:
+    if text is not None and ADDRESS_REGEXP.search(text) is not None:
         errors.append('Translation "%s" contains a bitcoin address. This will be removed.' % (text))
         return True
     return False