<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def string_to_date(value):
 """ Return a Python date that corresponds to the specified string representation. @param value: string representation of a date. @return: an instance ``datetime.datetime`` represented by the string. """

    if isinstance(value, datetime.date):
        return value

    return dateutil.parser.parse(value).date()