 The type conversion problem of array operations

```
a = np.array([0,255], dtype='uint8')
output：array([  0, 255], dtype=uint8)

a * 2
output：array([  0, 254], dtype=uint8) // become  the top eight after the operation

b = np.array([1, 255], dtype='uint8')
b * 256
output：array([  256, 65280], dtype=uint16) // Automatically become the type of uint16
```

The change of the variable type depends on the minimum of the array?