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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 timestamp(value, timezone=None):
 """ Returns a timestamp literal if value is likely coercible to a timestamp Parameters value : timestamp value as string timezone: timezone as string defaults to None Returns -------- result : TimestampScalar """

    if isinstance(value, str):
        try:
            value = pd.Timestamp(value, tz=timezone)
        except pd.errors.OutOfBoundsDatetime:
            value = dateutil.parser.parse(value)
    if isinstance(value, numbers.Integral):
        raise TypeError(
            (
                "Passing an integer to ibis.timestamp is not supported. Use "
                "ibis.literal({value:d}).to_timestamp() to create a timestamp "
                "expression from an integer."
            ).format(value=value)
        )
    return literal(value, type=dt.Timestamp(timezone=timezone))