Getting the list of arguments passed into the current function, while allowing keyword argument default values [closed]

I'm writing a function whose inner logic needs to know which optional keyword arguments the function was called with.

I also need to be able to specify default values for keyword arguments.

If an argument was specified in the call, it will behave one way; if that argument was not specified in the call but was instead taken from the default, it will use the default and will behave a different way.

I do have a working solution, but am wondering if there is a cleaner, safer, more concise way to accomplish the goal:

import json

def addFeature(*args,**kwargs):
    defaults={
        'p1':1,
        'p2':2,
        'p3':3
    }
    mergedKwargs = defaults | kwargs # start with defaults; overwrite with any specified kwargs items
    print(f'args:{args}')
    print('keyword arguments specified in the call to this function:')
    print(json.dumps(kwargs,indent=3))
    print('mergedKwargs:')
    print(json.dumps(mergedKwargs,indent=3))
    # unpack to local variables
    (p1,p2,p3)=(mergedKwargs[k] for k in ('p1','p2','p3'))
    print(f'local values: p1={p1}  p2={p2}  p3={p3}')

addFeature(1,2,p1=5)
addFeature(3,4,p2=7,p3=9)

running this code:

PS C:\Users\caver\Documents\GitHub> python argsTest.py
call to addFeature: args: (1, 2)
keyword arguments specified in the call to this function:
{
   "p1": 5
}
mergedKwargs:
{
   "p1": 5,
   "p2": 2,
   "p3": 3
}
local values: p1=5  p2=2  p3=3

call to addFeature: args: (3, 4)
keyword arguments specified in the call to this function:
{
   "p2": 7,
   "p3": 9
}
mergedKwargs:
{
   "p1": 1,
   "p2": 7,
   "p3": 9
}
local values: p1=1  p2=7  p3=9

PS C:\Users\caver\Documents\GitHub>

One drawback of this method is that the function signature (list of possible arguments) is unknown when using *args and **kwargs.