code: def read_prologue(self):
          
          with open(self.filename, "rb") as fp_:
              fp_.seek(self.mda['total_header_length'])
              data = np.fromfile(fp_, dtype=prologue, count=1)[0]
  
              self.prologue.update(recarray2dict(data))
  
          self.process_prologue()
docs: Read the prologue metadata.