class_docstr: Base file handler.
class_docstr_tok: ["Base","file","handler","."]
code: def _combine(infos, func, *keys):
      res = {}
      for key in keys:
          if key in infos[0]:
              res[key] = func([i[key] for i in infos])
  
      return res
  
imports: import numpy
  import xarray
  from pyresample.geometry import SwathDefinition
  from satpy.dataset import combine_metadata
  from satpy.readers import open_file_or_filename
label_desc: Use image node_id 7 for calling the BaseFileHandler obj's underlying member method code with example usage: obj._combine(infos, func) and returns: res