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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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changed = None
            
            first_process, lockfile = _get_lock(b_path)
            content = _read_password_file(b_path)
            if content is None or b_path == to_bytes('/dev/null'):
                plaintext_password = random_password(params['length'], chars)
                salt = None
                changed = True
            else:
                plaintext_password, salt = _parse_content(content)
            encrypt = params['encrypt']
            if encrypt and not salt:
                changed = True
                try:
                    salt = random_salt(BaseHash.algorithms[encrypt].salt_size)
                except KeyError:
                    salt = random_salt()
            if changed and b_path != to_bytes('/dev/null'):
                content = _format_content(plaintext_password, salt, encrypt=encrypt)
                _write_password_file(b_path, content)
            if first_process:
                
                _release_lock(lockfile)
            if encrypt:
                password = do_encrypt(plaintext_password, encrypt, salt=salt)
                ret.append(password)
            else:
                ret.append(plaintext_password)
        return ret