code: def _load_vertex_buffers(self):
          
          fd = gzip.open(cache_name(self.file_name), 'rb')
  
          for buff in self.meta.vertex_buffers:
  
              mat = self.wavefront.materials.get(buff['material'])
              if not mat:
                  mat = Material(name=buff['material'], is_default=True)
                  self.wavefront.materials[mat.name] = mat
  
              mat.vertex_format = buff['vertex_format']
              self.load_vertex_buffer(fd, mat, buff['byte_length'])
  
          fd.close()
docs: Load each vertex buffer into each material