Json string formatting with python

I'd like to know if there is any way to format the resulting strings of the enconding of some object with json in python. For example, suppose I have the following dictionary:

{'a': 12.73874, 'b': 1.74872, 'c': 8.27495}

and the result of the json encoding is:

{
    "c": 8.27495,
    "b": 1.74872,
    "a": 12.73874
}

while the result I want is:

{
    "a": 12.74,
    "c": 8.28,
    "b": 1.75
}

Notice the order of the elements and the decimal places of each number. Is there any way to do this?

Thanks in advance!