Here is an example of how you can create JSON.

#!/usr/bin/python
import json
raw_json   = '{"foo": "Hello", "bar": "World"}'
print(raw_json)

Which should print the following.

{"foo": "Hello", "bar": "World"}

json.loads can be used to parse the JSON.

#!/usr/bin/python3
import json
raw_json = '{"foo": "Hello", "bar": "World"}'

try:
  parsed_json = json.loads(raw_json)
except Exception as exception:
  print(f"Got the following exception: {exception}")

print(parsed_json)

Which should return the following.

{u'foo': u'Hello', u'bar': u'World'}

And here is how you can print the value of a certain key. This should print Hello in this example.

#!/usr/bin/python3
import json
raw_json = '{"foo": "Hello", "bar": "World"}'

try:
  parsed_json = json.loads(raw_json)
except Exception as exception:
  print(f"Got the following exception: {exception}")

print(parsed_json['foo'])

Let's say you reference a key that does not exist in the dictionary.

#!/usr/bin/python3
import json
raw_json = '{"foo": "Hello", "bar": "World"}'

try:
  parsed_json = json.loads(raw_json)
except Exception as exception:
  print(f"Got the following exception: {exception}")

print(parsed_json['bogus'])

This should raise a KeyError.

Traceback (most recent call last):
  File "example.py", line 6, in <module>
    print(parsed_json['bogus'])
KeyError: 'bogus'

try except else can be used to handle KeyError.

#!/usr/bin/python
import json
raw_json = '{"foo": "Hello", "bar": "World"}'
parsed_json = json.loads(raw_json)

try:
  parsed_json['bogus']
except KeyError:
  print("JSON does not contain key 'bogus'")
else:
  print(parsed_json['bogus'])

It's important to recognize that a dictionary is very similar to JSON, but not exactly the same.

#!/usr/bin/python
import json

dictionary =  {"foo": "Hello", "bar": "World"}
raw_json   = '{"foo": "Hello", "bar": "World"}'

print(type(dictionary))
print(dictionary)
print(type(raw_json))
print(raw_json)

Which should print the following, which shows that the dictionary type is dict whereas the JSON is actually a string, which can be seen by the fact that the JSON is wrapped in single quotes so that it's a string.

<type 'dict'>
{'foo': 'Hello', 'bar': 'World'}
<type 'str'>
{"foo": "Hello", "bar": "World"}