def add_boundary_ummg(ummg: dict, boundary_points: list):
    """
    Add boundary points list to UMMG in correct format
    Args:
        ummg: existing UMMG to augment
        boundary_points: list of lists, each major list entry is a pair of (lon, lat) coordinates

    Returns:
        dictionary representation of ummg
    """


    formatted_points_list = []
    for point in boundary_points:
        formatted_points_list.append({'Longitude': point[0], 'Latitude': point[1]})

    # For GPolygon, add the first point again to close out
    formatted_points_list.append({'Longitude': boundary_points[0][0], 'Latitude': boundary_points[0][1]})

    hsd = {"HorizontalSpatialDomain":
              {"Geometry":
                  {"GPolygons": [
                      {'Boundary':
                           {'Points': formatted_points_list}}
                  ]}
              }
          }


    ummg['SpatialExtent'] = hsd
    return ummg