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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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invalid_params = frozenset(params.keys()).difference(VALID_PARAMS)
    if invalid_params:
        raise AnsibleError('Unrecognized parameter(s) given to password lookup: %s' % ', '.join(invalid_params))
    
    params['length'] = int(params.get('length', DEFAULT_LENGTH))
    params['encrypt'] = params.get('encrypt', None)
    params['chars'] = params.get('chars', None)
    if params['chars']:
        tmp_chars = []
        if u',,' in params['chars']:
            tmp_chars.append(u',')
        tmp_chars.extend(c for c in params['chars'].replace(u',,', u',').split(u',') if c)
        params['chars'] = tmp_chars
    else:
        
        params['chars'] = [u'ascii_letters', u'digits', u".,:-_"]
    return relpath, params
def _read_password_file(b_path):
    """Read the contents of a password file and return it
    :arg b_path: A byte string containing the path to the password file
    :returns: a text string containing the contents of the password file or
        None if no password file was present.
    """
    content = None
    if os.path.exists(b_path):
        with open(b_path, 'rb') as f:
            b_content = f.read().rstrip()
        content = to_text(b_content, errors='surrogate_or_strict')
    return content
def _gen_candidate_chars(characters):