Convert all dates to string in pandas dataframe

date_to_string.py

def datetime_to_string(df):
    """
    Convert all datetimes to strings in a dataframe.
    Assumes dates are all timezone aware.
    """
    datetime_columns = df.select_dtypes(include="datetimetz").columns.to_list()
    for col in datetime_columns:
        df[col] = df[col].dt.strftime(date_format="%Y-%m-%dT%H:%M:%S%z")
    return df