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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 _get_error_values(self, startingPercentage, endPercentage, startDate, endDate):
 """Gets the defined subset of self._errorValues. Both parameters will be correct at this time. :param float startingPercentage: Defines the start of the interval. This has to be a value in [0.0, 100.0]. It represents the value, where the error calculation should be started. 25.0 for example means that the first 25% of all calculated errors will be ignored. :param float endPercentage: Defines the end of the interval. This has to be a value in [0.0, 100.0]. It represents the value, after which all error values will be ignored. 90.0 for example means that the last 10% of all local errors will be ignored. :param float startDate: Epoch representing the start date used for error calculation. :param float endDate: Epoch representing the end date used in the error calculation. :return: Returns a list with the defined error values. :rtype: list :raise: Raises a ValueError if startDate or endDate do not represent correct boundaries for error calculation. """

        if startDate is not None:
            possibleDates = filter(lambda date: date >= startDate, self._errorDates)
            if 0 == len(possibleDates):
                raise ValueError("%s does not represent a valid startDate." % startDate)

            startIdx = self._errorDates.index(min(possibleDates))
        else:
            startIdx = int((startingPercentage * len(self._errorValues)) / 100.0)

        if endDate is not None:
            possibleDates = filter(lambda date: date <= endDate, self._errorDates)
            if 0 == len(possibleDates):
                raise ValueError("%s does not represent a valid endDate." % endDate)

            endIdx = self._errorDates.index(max(possibleDates)) + 1
        else:
            endIdx = int((endPercentage * len(self._errorValues)) / 100.0)

        return self._errorValues[startIdx:endIdx]