at: PEP8 compliancy and doc fixes (#30881)

This PR includes:
- PEP8 compliancy fixes
- Documentation changes

lib/ansible/modules/system/at.py

@@ -1,22 +1,20 @@
 #!/usr/bin/python
 # -*- coding: utf-8 -*-
-#
-# (c) 2014, Richard Isaacson <richard.c.isaacson@gmail.com>
+
+# Copyright: (c) 2014, Richard Isaacson <richard.c.isaacson@gmail.com>
 # GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
 
 from __future__ import absolute_import, division, print_function
 __metaclass__ = type
 
-
 ANSIBLE_METADATA = {'metadata_version': '1.1',
                     'status': ['preview'],
                     'supported_by': 'core'}
 
-
 DOCUMENTATION = '''
 ---
 module: at
-short_description: Schedule the execution of a command or script file via the at command.
+short_description: Schedule the execution of a command or script file via the at command
 description:
  - Use this module to schedule a command or script file to run once in the future.
  - All jobs are executed in the 'a' queue.
@@ -25,13 +23,9 @@ options:
   command:
     description:
      - A command to be executed in the future.
-    required: false
-    default: null
   script_file:
     description:
      - An existing script file to be executed in the future.
-    required: false
-    default: null
   count:
     description:
      - The count of units in the future to execute the command or script file.
@@ -39,42 +33,42 @@ options:
   units:
     description:
      - The type of units in the future to execute the command or script file.
+    choices: [ minutes, hours, days, weeks ]
     required: true
-    choices: ["minutes", "hours", "days", "weeks"]
   state:
     description:
      - The state dictates if the command or script file should be evaluated as present(added) or absent(deleted).
-    required: false
-    choices: ["present", "absent"]
-    default: "present"
+    choices: [ absent, present ]
+    default: present
   unique:
     description:
      - If a matching job is present a new job will not be added.
-    required: false
-    default: false
+    type: bool
+    default: 'no'
 requirements:
  - at
-author: "Richard Isaacson (@risaacson)"
+author:
+- Richard Isaacson (@risaacson)
 '''
 
 EXAMPLES = '''
-# Schedule a command to execute in 20 minutes as root.
-- at:
-    command: "ls -d / > /dev/null"
+- name: Schedule a command to execute in 20 minutes as root.
+  at:
+    command: ls -d / >/dev/null
     count: 20
     units: minutes
 
-# Match a command to an existing job and delete the job.
-- at:
-    command: "ls -d / > /dev/null"
+- name: Match a command to an existing job and delete the job.
+  at:
+    command: ls -d / >/dev/null
     state: absent
 
-# Schedule a command to execute in 20 minutes making sure it is unique in the queue.
-- at:
-    command: "ls -d / > /dev/null"
-    unique: true
+- name: Schedule a command to execute in 20 minutes making sure it is unique in the queue.
+  at:
+    command: ls -d / >/dev/null
     count: 20
     units: minutes
+    unique: yes
 '''
 
 import os
@@ -140,43 +134,35 @@ def create_tempfile(command):
 def main():
 
     module = AnsibleModule(
-        argument_spec = dict(
-            command=dict(required=False,
-                         type='str'),
-            script_file=dict(required=False,
-                             type='str'),
-            count=dict(required=False,
-                       type='int'),
-            units=dict(required=False,
-                       default=None,
-                       choices=['minutes', 'hours', 'days', 'weeks'],
-                       type='str'),
-            state=dict(required=False,
-                       default='present',
-                       choices=['present', 'absent'],
-                       type='str'),
-            unique=dict(required=False,
-                        default=False,
-                        type='bool')
+        argument_spec=dict(
+            command=dict(type='str'),
+            script_file=dict(type='str'),
+            count=dict(type='int'),
+            units=dict(type='str', choices=['minutes', 'hours', 'days', 'weeks']),
+            state=dict(type='str', default='present', choices=['present', 'absent']),
+            unique=dict(type='bool', default=False),
         ),
         mutually_exclusive=[['command', 'script_file']],
         required_one_of=[['command', 'script_file']],
-        supports_check_mode=False
+        supports_check_mode=False,
     )
 
     at_cmd = module.get_bin_path('at', True)
 
-    command        = module.params['command']
-    script_file    = module.params['script_file']
-    count          = module.params['count']
-    units          = module.params['units']
-    state          = module.params['state']
-    unique         = module.params['unique']
+    command = module.params['command']
+    script_file = module.params['script_file']
+    count = module.params['count']
+    units = module.params['units']
+    state = module.params['state']
+    unique = module.params['unique']
 
     if (state == 'present') and (not count or not units):
         module.fail_json(msg="present state requires count and units")
 
-    result = {'state': state, 'changed': False}
+    result = dict(
+        changed=False,
+        state=state,
+    )
 
     # If command transform it into a script_file
     if command:

test/sanity/pep8/legacy-files.txt

@@ -335,7 +335,6 @@ lib/ansible/modules/storage/netapp/sf_volume_access_group_manager.py
 lib/ansible/modules/storage/netapp/sf_volume_manager.py
 lib/ansible/modules/storage/zfs/zfs.py
 lib/ansible/modules/system/aix_inittab.py
-lib/ansible/modules/system/at.py
 lib/ansible/modules/system/capabilities.py
 lib/ansible/modules/system/cronvar.py
 lib/ansible/modules/system/crypttab.py