code: def find_file(self, filename: str, strip_path: bool = True, what='exposure') -> str:
          
          if what == 'exposure':
              path = self._path
          elif what == 'header':
              path = self._headerpath
          elif what == 'mask':
              path = self._maskpath
          else:
              path = self._path
          tried = []
          if strip_path:
              filename = os.path.split(filename)[-1]
          for d in path:
              if os.path.exists(os.path.join(d, filename)):
                  tried.append(os.path.join(d, filename))
                  return os.path.join(d, filename)
          raise FileNotFoundError('Not found: {}. Tried: {}'.format(filename, ', '.join(tried)))
docs: Find file in the path