code: def convert(self):
      if self.ppm.shape[-1] == self.mixmat.shape[0]:
          self.ppm = np.dot(self.ppm, self.mixmat)
          self.label = map_from_ppm(self.ppm, self.mask)
  
imports: import numpy
  from .segmentation import Segmentation, map_from_ppm, moment_matching
label_desc: Use image node_id 4 for calling the BrainT1Segmentation obj's underlying member method code with example usage: obj.convert() without return types