code: def get_default_gwf_api():
      
      for lib in APIS:
          try:
              import_gwf_library(lib)
          except ImportError:
              continue
          else:
              return lib
      raise ImportError("no GWF API available, please install a third-party GWF "
                        "library ({}) and try again".format(', '.join(APIS)))
docs: Return the preferred GWF library
  
      Examples
      --------
      If you have |LDAStools.frameCPP|_ installed:
  
      >>> from gwpy.timeseries.io.gwf import get_default_gwf_api
      >>> get_default_gwf_api()
      'framecpp'
  
      Or, if you don't have |lalframe|_:
  
      >>> get_default_gwf_api()
      'lalframe'
  
      Otherwise:
  
      >>> get_default_gwf_api()
      ImportError: no GWF API available, please install a third-party GWF
      library (framecpp, lalframe) and try again