How to use the pygmsh.built_in.point_base.PointBase function in pygmsh

def add_physical(self, entities, label=None):
        if not isinstance(entities, list):
            entities = [entities]

        d = {0: "Point", 1: "Line", 2: "Surface", 3: "Volume"}
        tpe = d[entities[0].dimension]

        for e in entities:
            assert isinstance(
                e,
                (
                    Point,
                    PointBase,
                    LineBase,
                    Surface,
                    PlaneSurface,
                    SurfaceBase,
                    Volume,
                    VolumeBase,
                ),
            ), "Can add physical groups only for Points, Lines, Surfaces, Volumes, not {}.".format(
                type(e)
            )
            assert d[e.dimension] == tpe

        label = self._new_physical_group(label)
        self._GMSH_CODE.append(
            "Physical {}({}) = {{{}}};".format(
                tpe, label, ", ".join([e.id for e in entities])

# > programatically by saving the output of the command into a
        # > list. This list will contain the "top" of the extruded surface (in
        # > out[0]) as well as the newly created volume (in out[1]).
        #
        top = f"{name}[0]"
        extruded = f"{name}[1]"

        if isinstance(input_entity, LineBase):
            top = LineBase(top)
            # A surface extruded from a single line has always 4 edges
            extruded = SurfaceBase(extruded, 4)
        elif isinstance(input_entity, (SurfaceBase, self.Polygon)):
            top = SurfaceBase(top, input_entity.num_edges)
            extruded = VolumeBase(extruded)
        elif isinstance(input_entity, PointBase):
            top = PointBase(top)
            extruded = LineBase(extruded)
        else:
            top = Dummy(top)
            extruded = Dummy(extruded)

        lat = []
        # lateral surfaces can be deduced only if we start from a SurfaceBase
        # or a Polygon
        if isinstance(input_entity, (SurfaceBase, self.Polygon)):
            # out[0]` is the surface, out[1] the top, and everything after that
            # the sides, cf.
            # . Each
            # lateral surface has 4 edges: the one from input_entity, the one
            # from top, and the two lines (or splines) connecting their extreme
            # points.
            lat = [

def __init__(self, id0=None):
        if id0:
            self.id = id0
        else:
            self.id = f"p{PointBase._ID}"
            PointBase._ID += 1
        return

from .point_base import PointBase


class Point(PointBase):
    """
    Creates an elementary point.

    x : array-like[3]
        Give the three X, Y and Z coordinates of the
        point in the three-dimensional Euclidean space.
    lcar : float
        The prescribed mesh element size at this point.
    """

    def __init__(self, x, lcar=None):
        super().__init__()

        self.x = x
        self.lcar = lcar

# > In this last extrusion command we retrieved the volume number
        # > programatically by saving the output of the command into a
        # > list. This list will contain the "top" of the extruded surface (in
        # > out[0]) as well as the newly created volume (in out[1]).
        #
        top = f"{name}[0]"
        extruded = f"{name}[1]"

        if isinstance(input_entity, LineBase):
            top = LineBase(top)
            # A surface extruded from a single line has always 4 edges
            extruded = SurfaceBase(extruded, 4)
        elif isinstance(input_entity, (SurfaceBase, self.Polygon)):
            top = SurfaceBase(top, input_entity.num_edges)
            extruded = VolumeBase(extruded)
        elif isinstance(input_entity, PointBase):
            top = PointBase(top)
            extruded = LineBase(extruded)
        else:
            top = Dummy(top)
            extruded = Dummy(extruded)

        lat = []
        # lateral surfaces can be deduced only if we start from a SurfaceBase
        # or a Polygon
        if isinstance(input_entity, (SurfaceBase, self.Polygon)):
            # out[0]` is the surface, out[1] the top, and everything after that
            # the sides, cf.
            # . Each
            # lateral surface has 4 edges: the one from input_entity, the one
            # from top, and the two lines (or splines) connecting their extreme
            # points.