code: def path(self):
          
          if (self.source_file.startswith('a/') and
                  self.target_file.startswith('b/')):
              filepath = self.source_file[2:]
          elif (self.source_file.startswith('a/') and
                self.target_file == '/dev/null'):
              filepath = self.source_file[2:]
          elif (self.target_file.startswith('b/') and
                self.source_file == '/dev/null'):
              filepath = self.target_file[2:]
          else:
              filepath = self.source_file
          return filepath
docs: Return the file path abstracted from VCS.