def normalize_column_names(df):
    r""" Clean up whitespace in column names. See better version at `pugnlp.clean_columns`

    >>> df = pd.DataFrame([[1, 2], [3, 4]], columns=['Hello World', 'not here'])
    >>> normalize_column_names(df)
    ['hello_world', 'not_here']
    """
    columns = df.columns if hasattr(df, 'columns') else df
    columns = [c.lower().replace(' ', '_') for c in columns]
    return columns
def normalize_column_names ( df ) : columns = df . columns if hasattr ( df , 'columns' ) else df columns = [ c . lower ( ) . replace ( ' ' , '_' ) for c in columns ] return columns
r""" Clean up whitespace in column names. See better version at `pugnlp.clean_columns`

    >>> df = pd.DataFrame([[1, 2], [3, 4]], columns=['Hello World', 'not here'])
    >>> normalize_column_names(df)
    ['hello_world', 'not_here']