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##### SUMMARY
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https://docs.ansible.com/ansible/latest/collections/ansible/builtin/password_lookup.html :

> Define comma separated list of names that compose a custom character set in the generated passwords.
> They can be either parts of Python's string module attributes (ascii_letters,digits, etc) or are used literally ( :, -).

I suggest to list all possible names or at least add a link to python string module documentation: https://docs.python.org/3/library/string.html

Now you have to search for the relevant python documentation yourself.

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##### ISSUE TYPE
- Documentation Report

##### COMPONENT NAME
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ansible.builtin.password

##### ADDITIONAL INFORMATION
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"""Get the lock for writing password file."""
    first_process = False
    b_pathdir = os.path.dirname(b_path)
    lockfile_name = to_bytes("%s.ansible_lockfile" % hashlib.sha1(b_path).hexdigest())
    lockfile = os.path.join(b_pathdir, lockfile_name)
    if not os.path.exists(lockfile) and b_path != to_bytes('/dev/null'):
        try:
            makedirs_safe(b_pathdir, mode=0o700)
            fd = os.open(lockfile, os.O_CREAT | os.O_EXCL)
            os.close(fd)
            first_process = True
        except OSError as e:
            if e.strerror != 'File exists':
                raise
    counter = 0
    
    while os.path.exists(lockfile) and not first_process:
        time.sleep(2 ** counter)
        if counter >= 2:
            raise AnsibleError("Password lookup cannot get the lock in 7 seconds, abort..."
                               "This may caused by un-removed lockfile"
                               "you can manually remove it from controller machine at %s and try again" % lockfile)
        counter += 1
    return first_process, lockfile
def _release_lock(lockfile):
    """Release the lock so other processes can read the password file."""
    if os.path.exists(lockfile):
        os.remove(lockfile)
class LookupModule(LookupBase):