Fix issues discovered by common python linters

Fix some issues discovered by common python linters including:
* switch `None` comparisons to use `is` rather than `==`. Identity !=
equality, and I've spent 40+ hours before tracking down a subtle bug
caused by exactly this issue. Note that this may introduce a problem if
one of the scripts is depending on this behavior, in which case the
comparison should be changed to `True`/`False` rather than `None`.
* Use `except Exception:` as bare `except:` statements have been
discouraged for years. Ideally for some of these we'd examine if there
were specific exceptions that should be caught, but for now I simply
caught all. Again, this could introduce very subtle behavioral changes
under Python 2, but IIUC, that was all fixed in Python 3, so safe to
move to `except Exception:`.
* Use more idiomatic `if not x in y`--> `if x not in y`
* Use more idiomatic 2 blank lines. I only did this at the beginning,
until I realized how overwhelming this was going to be to apply, then I
stopped.
* Add a TODO where an undefined function name is called, so will fail
whenever that code is run.
* Add more idiomatic spacing around `:`. This is also only partially
cleaned up, as I gave up when I saw how `asn2wrs.py` was clearly
infatuated with the construct.
* Various other small cleanups, removed some trailing whitespace and
improper indentation that wasn't a multiple of 4, etc.

There is still _much_ to do, but I haven't been heavily involved with
this project before, so thought this was a sufficient amount to put up
and see what the feedback is.

Linters that I have enabled which highlighted some of these issues
include:
* `pylint`
* `flake8`
* `pycodestyle`

1 files changed, 7 insertions, 2 deletions

diff --git a/tools/netscreen2dump.py b/tools/netscreen2dump.py
index 78312bc536..7aaac94b7d 100755
--- a/tools/netscreen2dump.py
+++ b/tools/netscreen2dump.py
@@ -13,6 +13,7 @@ import os
 import stat
 import time
 
+
 class OutputFile:
     TIMER_MAX = 99999.9
 
@@ -28,11 +29,11 @@ class OutputFile:
     def PrintPacket(self, timestamp, datalines):
         # What do to with the timestamp? I need more data about what
         # the netscreen timestamp is, then I can generate one for the text file.
-#        print "TS:", timestamp.group("time")
+        #     print("TS:", timestamp.group("time"))
         try:
             timestamp = float(timestamp.group("time"))
         except ValueError:
-            sys.exit("Unable to convert '%s' to floating point." % \
+            sys.exit("Unable to convert '%s' to floating point." %
                     (timestamp,))
 
         # Did we wrap around the timeer max?
@@ -63,12 +64,14 @@ class OutputFile:
         # Blank line
         print >> self.fh
 
+
 # Find a timestamp line
 re_timestamp = re.compile(r"^(?P<time>\d+\.\d): [\w/]+\((?P<io>.)\)(:| len=)")
 
 # Find a hex dump line
 re_hex_line = re.compile(r"(?P<hex>([0-9a-f]{2} ){1,16})\s+(?P<ascii>.){1,16}")
 
+
 def run(input_filename, output_filename):
     try:
         ifh = open(input_filename, "r")
@@ -122,11 +125,13 @@ def usage():
     print >> sys.stderr, "Usage: netscreen2dump.py netscreen-dump-file new-dump-file"
     sys.exit(1)
 
+
 def main():
     if len(sys.argv) != 3:
         usage()
 
     run(sys.argv[1], sys.argv[2])
 
+
 if __name__ == "__main__":
     main()