def ftdetect(filename):
    """Determine if filename is markdown or notebook,
    based on the file extension.
    """
    _, extension = os.path.splitext(filename)
    md_exts = ['.md', '.markdown', '.mkd', '.mdown', '.mkdn', '.Rmd']
    nb_exts = ['.ipynb']
    if extension in md_exts:
        return 'markdown'
    elif extension in nb_exts:
        return 'notebook'
    else:
        return None
def ftdetect ( filename ) : _ , extension = os . path . splitext ( filename ) md_exts = [ '.md' , '.markdown' , '.mkd' , '.mdown' , '.mkdn' , '.Rmd' ] nb_exts = [ '.ipynb' ] if extension in md_exts : return 'markdown' elif extension in nb_exts : return 'notebook' else : return None
Determine if filename is markdown or notebook,
    based on the file extension.