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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _parse_date_columns(data_frame, parse_dates):
 """ Force non-datetime columns to be read as such. Supports both string formatted and integer timestamp columns. """

    parse_dates = _process_parse_dates_argument(parse_dates)

    # we want to coerce datetime64_tz dtypes for now to UTC
    # we could in theory do a 'nice' conversion from a FixedOffset tz
    # GH11216
    for col_name, df_col in data_frame.iteritems():
        if is_datetime64tz_dtype(df_col) or col_name in parse_dates:
            try:
                fmt = parse_dates[col_name]
            except TypeError:
                fmt = None
            data_frame[col_name] = _handle_date_column(df_col, format=fmt)

    return data_frame