Localize a timestamp column

localize_df.py

import pytz
import pandas as pd

def localize_datetime(input_df, timezone='Europe/Paris',
                      datetime_column='tms_gmt'):
    """
    Convert datetime column from UTC to another timezone.
    """
    tmz = pytz.timezone(timezone)
    df = input_df.copy()
    return (df.set_index(datetime_column)
              .tz_localize(pytz.utc)  # UTC time
              .tz_convert(tmz)  # Timezone time
              .reset_index())
  
 def delocalize_datetime(input_df, timezone='Europe/Paris',
                         datetime_column='tms'):
    """
    Convert datetime column from a timezone to UTC.
    """
    tmz = pytz.timezone(timezone)
    df = input_df.copy()
    return (df.set_index(datetime_column)
              .tz_localize(tmz, ambiguous=True)   # Timezone time
              .tz_convert(pytz.utc)  # UTC time
              .reset_index())  
  
DATA_PATH = 'path/to/csv'
TIMEZONE = 'your/timezone'
  
df = (pd.read_csv(DATA_PATH)
        .assign(tms=lambda df: pd.to_datetime(df.tms_gmt))
        .pipe(localize_datetime, datetime_column='tms', timezone=TIMEZONE)
        .drop('tms_gmt', axis=1))