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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def user_roles_exists(name, roles, database, user=None, password=None, host=None,
                      port=None, authdb=None):
    '''
    Checks if a user of a MongoDB database has specified roles

    CLI Examples:

    .. code-block:: bash

        salt '*' mongodb.user_roles_exists johndoe '["readWrite"]' dbname admin adminpwd localhost 27017

    .. code-block:: bash

        salt '*' mongodb.user_roles_exists johndoe '[{"role": "readWrite", "db": "dbname" }, {"role": "read", "db": "otherdb"}]' dbname admin adminpwd localhost 27017
    '''
    try:
        roles = _to_dict(roles)
    except Exception:
        return 'Roles provided in wrong format'

    users = user_list(user, password, host, port, database, authdb)

    if isinstance(users, six.string_types):
        return 'Failed to connect to mongo database'

    for user in users:
        if name == dict(user).get('user'):
            for role in roles:
                # if the role was provided in the shortened form, we convert it to a long form
                if not isinstance(role, dict):
                    role = {'role': role, 'db': database}
                if role not in dict(user).get('roles', []):
                    return False
            return True

    return False