# cf.close_files

`cf.``close_files`(file_format=None)

  Close open files containing sub-arrays of data arrays.

  By default all such files are closed, but this may be restricted to files of a particular format.

  Note that closed files will be automatically reopened if subsequently needed by a variable to access the sub-array.

  If there are no appropriate open files then no action is taken.

  See also

  `cf.close_one_file`, `cf.open_files`, `cf.open_files_threshold_exceeded`

  Parameters: | file_format : str, optional Only close files of the given format. Recognised formats are `'netCDF'` and `'PP'`. By default files of any format are closed.
  Returns: | None
  Examples: |

      >>> cf.close_files()
      >>> cf.close_files('netCDF')
      >>> cf.close_files('PP')