Get elt properties.

    :param elt: properties elt. Not None methods or unhashable types.
    :param keys: key(s) of properties to get from elt.
        If None, get all properties.
    :type keys: list or str
    :param ctx: elt ctx from where get properties. Equals elt if None. It
        allows to get function properties related to a class or instance if
        related function is defined in base class.

    :return: list of properties by elt and name.
    :rtype: list

def get_properties(elt, keys=None, ctx=None):
    """Get elt properties.

    :param elt: properties elt. Not None methods or unhashable types.
    :param keys: key(s) of properties to get from elt.
        If None, get all properties.
    :type keys: list or str
    :param ctx: elt ctx from where get properties. Equals elt if None. It
        allows to get function properties related to a class or instance if
        related function is defined in base class.

    :return: list of properties by elt and name.
    :rtype: list
    """

    # initialize keys if str
    if isinstance(keys, string_types):
        keys = (keys,)

    result = _get_properties(elt, keys=keys, local=False, ctx=ctx)

    return result