code: def load_lib():
      global _fits
      try:
          from astropy.io import fits as _fits
      except ImportError:
          raise ImportError(
              "The FITS format relies on the astropy package."
              "Please refer to http://www.astropy.org/ "
              "for further instructions."
          )
      return _fits
  
imports: from ..core import Format
label_desc: Use image node_id 1 for calling a global function with example usage: load_lib() and returns: _fits