code: def write(self, fptr):
          
          self._validate(writing=True)
          length = 16 + 4 * len(self.compatibility_list)
          fptr.write(struct.pack('>I4s', length, b'ftyp'))
          fptr.write(self.brand.encode())
          fptr.write(struct.pack('>I', self.minor_version))
  
          for item in self.compatibility_list:
              fptr.write(item.encode())
docs: Write a File Type box to file.