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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 _ExtractRequestSummaryFields(self, request, error=None):
 """Extract fields used in the summary logs. Args: request: a urllib2.Request instance configured to make the request. [optional] error: a urllib2.HttpError instance used to retrieve error details. Returns: A dict containing the fields to be output in the summary logs. """

    headers = request.headers
    summary_fields = {
        'server': request.get_full_url(),
        'contentRange': headers['Content-range'],
        'contentLength': headers['Content-length']
    }

    if error:
      summary_fields['isError'] = True
      summary_fields['errorMessage'] = error.reason
    else:
      summary_fields['isError'] = False

    return summary_fields