I want to find the max value of a 3d array in python.
I tried

```
image_file1 = open("lena256x256.bmp","rb")
img_i = PIL.Image.open(image_file1)
pix = numpy.array(img_i);
maxval= max(pix)

```

but i am getting an error

```
 File "test.py", line 31, in <module>
    maxval= max(pix)
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

```

I cannot catch my mistake here, please help me.