How do I instantiate a class with **kwargs?

[palladium]

Consider the following:

class TestClass():

    def __init__(self, param_1 , **kwargs):
        self.param_1 = param_1
        #?? how do I initialise the **kwargs??
        #self.**kwargs = **kwargs gives a SyntaxError
    
    def do_something(self):
        pass

x = TestClass(param_1 = 'a', param_2 = 'b', param_3 = 'c')
print(x.param_1) #a
print(x.param_2) #AttributeError : TestClass object has no attribute 'param_2'

How do I get the final line to work?

Thanks in advance