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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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"""Hacky parsing of params
    See https://github.com/ansible/ansible-modules-core/issues/1968#issuecomment-136842156
    and the first_found lookup For how we want to fix this later
    """
    first_split = term.split(' ', 1)
    if len(first_split) <= 1:
        
        relpath = term
        params = dict()
    else:
        relpath = first_split[0]
        params = parse_kv(first_split[1])
        if '_raw_params' in params:
            
            relpath = u' '.join((relpath, params['_raw_params']))
            del params['_raw_params']
            
            if not term.startswith(relpath):
                
                
                raise AnsibleError('Unrecognized value after key=value parameters given to password lookup')