code: def is_modified(self) -> bool:
          
          if self.is_new or self.is_deleted:
              return False
          return self.left.md5 != self.right.md5
docs: Find whether the files on the left and right are different. Note,
          modified implies the contents of the file have changed, which is
          predicated on the file existing on both the left and right. Therefore
          this will be false if the file on the left has been deleted, or the
          file on the right is new.
  
          :return: Whether the file has been modified.