ByteMultiArray publish fails if data > 10 bytes

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I have next code:

data = file.read()  
arr = ByteMultiArray()  
arr.data = list(bytearray(data))  
arr.layout.dim.append(MultiArrayDimension())  
arr.layout.dim[0].label = "soundfile"  
arr.layout.dim[0].size = len(arr.data)  
arr.layout.dim[0].stride = len(arr.data)  
arr.layout.data_offset = 0  
pub.publish(arr)

When data 10 and less publish succeed When data > 10 I have

rospy.exceptions.ROSSerializationException: field data[] exceeds specified width [byte]