def _get_content(data, refname):
    """
    Return string-content of an XML text node.

    :arg data: A minidom object.
    :arg refname: The name of a member of the minidom object.

    :return: The content of the textnode or an emtpy string.
    :rtype: string
    """
    temp = data.getElementsByTagName(refname)
    if temp:
        return temp[0].lastChild.data
    return None