code: def export_stl(mesh):
      
      header = np.zeros(1, dtype=_stl_dtype_header)
      header['face_count'] = len(mesh.faces)
  
      packed = np.zeros(len(mesh.faces), dtype=_stl_dtype)
      packed['normals'] = mesh.face_normals
      packed['vertices'] = mesh.triangles
  
      export = header.tostring()
      export += packed.tostring()
  
      return export
docs: Convert a Trimesh object into a binary STL file.
  
      Parameters
      ---------
      mesh: Trimesh object
  
      Returns
      ---------
      export: bytes, representing mesh in binary STL form