Find max value in json even when not existing in some strings Python

I have a json like this:

{
'tester': [{
    'bbox': [159.50451898338267, 184.94235347135182, 342.8551702886517, 443.9425698127003],
    'score': 0.9999966621398926,
    'post': 43.10764727758942,
    'class': 'Test'
}, {
    'bbox': [564.0261332136855, 14.13539395667492, 580.3409768964439, 38.84439850201004],
    'score': 0.9937067627906799
}, {
    'bbox': [462.02023603048644, 10.929288388749383, 477.8772119836293, 29.733179334594],
    'score': 0.9837657809257507
}],
'status': 'ok'

}

The json can contain more strings.

Im trying to get the max value from Post using this code:

max_age = max(quality['tester'], key=lambda x: x['post'])

The problem im facing is that the key Post does not exists in every string so I get a key error using this code

>Solution :

Assuming you want to ignore entries that do not contain the post key, this should work:

max_age = max(filter(lambda x: 'post' in x, quality['tester']), key=lambda x: x['post'])

You may also want to provide a default value (otherwise max will crash if there is the sequence is empty), or even this variant if you are only interested in the maximum post value, and not the entry whose post value is maximal:

max_age = max(x['post'] for x in quality['tester'] if 'post' in x))