code: def get_index(self, fname):
          
  
          idx, = np.where(fname == self.files)
          if len(idx) == 0:
              # filename not in index, try reloading files from disk
              self.refresh()
              #print("DEBUG get_index:", fname, self.files)
              idx, = np.where(fname == np.array(self.files))
  
              if len(idx) == 0:
                  raise ValueError('Could not find "' + fname +
                                   '" in available file list. Valid Example: ' +
                                   self.files.iloc[0])
          # return a scalar rather than array - otherwise introduces array to
          # index warnings.
          return idx[0]
docs: Return index for a given filename. 
          
          Parameters
          ----------
          fname : string
              filename
          
          Note
          ----
          If fname not found in the file information already attached 
          to the instrument.files instance, then a files.refresh() call 
          is made.