def is_not_null(df: DataFrame, col_name: str) -> bool:
    """
    Return ``True`` if the given DataFrame has a column of the given
    name (string), and there exists at least one non-NaN value in that
    column; return ``False`` otherwise.
    """
    if (
        isinstance(df, pd.DataFrame)
        and col_name in df.columns
        and df[col_name].notnull().any()
    ):
        return True
    else:
        return False
def is_not_null ( df : DataFrame , col_name : str ) -> bool : if ( isinstance ( df , pd . DataFrame ) and col_name in df . columns and df [ col_name ] . notnull ( ) . any ( ) ) : return True else : return False
Return ``True`` if the given DataFrame has a column of the given
    name (string), and there exists at least one non-NaN value in that
    column; return ``False`` otherwise.