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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 init_defaults(self):
 """Initializes important headers to default values, if not already specified. The WARC-Record-ID header is set to a newly generated UUID. The WARC-Date header is set to the current datetime. The Content-Type is set based on the WARC-Type header. The Content-Length is initialized to 0. """

        if "WARC-Record-ID" not in self:
            self['WARC-Record-ID'] = "<urn:uuid:%s>" % uuid.uuid1()
        if "WARC-Date" not in self:
            self['WARC-Date'] = datetime.datetime.utcnow().strftime('%Y-%m-%dT%H:%M:%SZ')
        if "Content-Type" not in self:
            self['Content-Type'] = WARCHeader.CONTENT_TYPES.get(self.type, "application/octet-stream")