Meta: Resolve some pylint violations in Python lint scripts

Resolves:

* all: consider-using-sys-exit
* all: wrong-import-order
* all: TODO: Require that a few keys are set? (fixme)
* some: missing-function-docstring
* some: line-too-long

Meta/lint-ports.py

@@ -2,20 +2,42 @@
 
 import os
 import re
+import sys
 
 # Matches e.g. "| [`bash`]..." and captures "bash" in group 1
 PORT_TABLE_REGEX = re.compile(r'^\| \[`([^`]+)`\][^`]+$', re.MULTILINE)
 
 PORT_TABLE_FILE = 'AvailablePorts.md'
-IGNORE_FILES = {'.gitignore', '.port_include.sh', PORT_TABLE_FILE, 'build_all.sh', 'build_installed.sh', 'ReadMe.md'}
+IGNORE_FILES = {
+    '.gitignore',
+    '.port_include.sh',
+    PORT_TABLE_FILE,
+    'build_all.sh',
+    'build_installed.sh',
+    'ReadMe.md'
+}
 
 
 def read_port_table(filename):
+    """Open a file and find all PORT_TABLE_REGEX matches.
+
+    Args:
+        filename (str): file name
+
+    Returns:
+        set: all PORT_TABLE_REGEX matches
+    """
     with open(filename, 'r') as fp:
         return set(PORT_TABLE_REGEX.findall(fp.read()))
 
 
 def read_port_dirs():
+    """Check Ports directory for unexpected files and check each port has a package.sh file.
+
+    Returns:
+        list: all ports (set), errors encountered (bool)
+    """
+
     ports = set()
     all_good = True
     for entry in os.listdir():
@@ -35,6 +57,8 @@ def read_port_dirs():
 
 
 def run():
+    """Check Ports directory contents for errors."""
+
     from_table = read_port_table(PORT_TABLE_FILE)
     from_fs, all_good = read_port_dirs()
 
@@ -51,12 +75,11 @@ def run():
             print('    {}'.format(port))
 
     if not all_good:
-        exit(1)
+        sys.exit(1)
 
     print('No issues found.')
 
 
 if __name__ == '__main__':
     os.chdir(os.path.dirname(__file__) + "/../Ports")
-    # Ignore argv
     run()