def get_docstring(obj):
    """
    Returns docstring for a given object or empty string if no-object is provided or there is no docstring for it.

    :param obj: Object for which the docstring to be provided
    :return: Docstring
    """
    if obj is None:
        return ''

    doc = obj.__doc__
    if doc is None:
        return ''
    else:
        return doc