Python's assert_called_with, is there a wildcard character?

Suppose I have a class in python set up like this.

from somewhere import sendmail

class MyClass:

    def __init__(self, **kargs):
        self.sendmail = kwargs.get("sendmail", sendmail)  #if we can't find it, use imported def

    def publish():

        #lots of irrelevant code
        #and then

        self.sendmail(mail_to, mail_from, subject, body, format= 'html')

So as you can see, I have sort of given myself the option to parameterize which function I use for self.sendmail

Now in the test file.

Class Tester():

    kwargs = {"sendmail": MagicMock(mail_from= None, mail_to= None, subject= None, body= None, format= None)}
    self.myclass = MyClass(**kwargs)

    ##later on
    def testDefaultEmailHeader():

        default_subject = "Hello World"
        self.myclass.publish()

        self.myclass.sendmail.assert_called()  #this is doing just fine
        self.myclass.sendmail.assert_called_with(default_subject)  #this is having issues

For some reason I am getting the error message

AssertionError: Expected call: mock('Hello World')
                Actual Call : mock('defaultmt', 'defaultmf', 'Hello World', 'default_body', format= 'html')

So basically, the assert is expecting sendmail to be called with only one variable, when it ends up being called with all 5. The thing is, I don't care about what the other 4 variables are! I just want to make sure it is called with the correct subject.

I tried the mock place holder ANY, and got the same thing

self.myclass.sendmail.assert_called_with(ANY, ANY, 'Hello World', ANY, ANY)

AssertionError: Expected call: mock(<ANY>, <ANY>, 'Hello World', <ANY>, <ANY>)
Actual Call : mock('defaultmt', 'defaultmf', 'Hello World', 'default_body, 'format= 'html') 

Really unsure on how to proceed with this one. Anyone have any advice if we only care about one of the variable and want to ignore the rest?