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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 expectedBody(self, data):
 """ Read header and wait header value to call next state @param data: Stream that length are to header length (1|2|4 bytes) set next state to callBack body when length read from header are received """

        bodyLen = None
        if data.len == 1:
            bodyLen = UInt8()
        elif data.len == 2:
            bodyLen = UInt16Be()
        elif data.len == 4:
            bodyLen = UInt32Be()
        else:
            log.error("invalid header length")
            return
        data.readType(bodyLen)
        self.expect(bodyLen.value, self._callbackBody)