code: def check_cmfcc(cls):
          
          if gf.can_run_c_extension("cmfcc"):
              gf.print_success(u"aeneas.cmfcc   AVAILABLE")
              return False
          gf.print_warning(u"aeneas.cmfcc   NOT AVAILABLE")
          gf.print_info(u"  You can still run aeneas but it will be significantly slower")
          gf.print_info(u"  Please refer to the installation documentation for details")
          return True
docs: Check whether Python C extension ``cmfcc`` can be imported.
  
          Return ``True`` on failure and ``False`` on success.
  
          :rtype: bool