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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 get_all_users(path_prefix='/', region=None, key=None, keyid=None,
                 profile=None):
    '''
    Get and return all IAM user details, starting at the optional path.

    .. versionadded:: 2016.3.0

    CLI Example:

        salt-call boto_iam.get_all_users
    '''
    conn = _get_conn(region=region, key=key, keyid=keyid, profile=profile)
    if not conn:
        return None
    _users = conn.get_all_users(path_prefix=path_prefix)
    users = _users.list_users_response.list_users_result.users
    marker = getattr(
        _users.list_users_response.list_users_result, 'marker', None
    )
    while marker:
        _users = conn.get_all_users(path_prefix=path_prefix, marker=marker)
        users = users + _users.list_users_response.list_users_result.users
        marker = getattr(
            _users.list_users_response.list_users_result, 'marker', None
        )
    return users