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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 add_size_info (self):
 """Get size of URL content from HTTP header."""

        if self.headers and "Content-Length" in self.headers and \
           "Transfer-Encoding" not in self.headers:
            # Note that content-encoding causes size differences since
            # the content data is always decoded.
            try:
                self.size = int(self.getheader("Content-Length"))
            except (ValueError, OverflowError):
                pass
        else:
            self.size = -1