def get_nsb(root_tree):
    """Search 3 items 'nsb', 'nsb-name' and 'nsb-value' in the tree.

    Args:
        root_tree: the root of XML tree object.

    Returns:
        A List contains all necessary name space binding configuration
        encapsulated in a tuple.

    """
    out = []
    for i in root_tree.iter('nsb'):
        bind_id = i.attrib['id']
        key_value = i.find('nsb-name').attrib['value']
        string_value = i.find('nsb-value').attrib['value']
        out.append((bind_id, key_value, string_value))
    return out