pip install pygeosimplify

import pygeosimplify as pgs
from pygeosimplify.simplify.layer import GeoLayer
from pygeosimplify.simplify.detector import SimplifiedDetector

# Set names of branches that specify coordinate system of cells
pgs.set_coordinate_branch("XYZ", "isCartesian")

# Load geometry
geo = pgs.load_geometry("DetectorCells.root", tree_name='treeName')

# Create simplified detector
detector = SimplifiedDetector()

# Add dector layers to detector
layer = GeoLayer(geo, layer_idx)
detector.add_layer(layer)

# Process detector
detector.process()

# Save simplified detector to gdml file
detector.save_to_gdml(cyl_type='processed', output_path='processed.gdml')