code: def use(wcspkg, raise_err=True):
      
      global coord_types, wcs_configured, WCS
  
      if wcspkg not in common.custom_wcs:
          # Try to dynamically load WCS
          modname = 'wcs_%s' % (wcspkg)
          path = os.path.join(wcs_home, '%s.py' % (modname))
          try:
              my_import(modname, path)
          except ImportError:
              return False
  
      if wcspkg in common.custom_wcs:
          bnch = common.custom_wcs[wcspkg]
          WCS = bnch.wrapper_class
          coord_types = bnch.coord_types
          wcs_configured = True
          return True
  
      return False
docs: Choose WCS package.