add_header expecting 3 arguments instead of just key/value

Question

I'm encountering this error message: `TypeError: add_header() takes exactly 3 arguments (2 given)` when using these parameters: `testService("SomeServiceName", "POST", "[redacted valid url]", ('Content-type','application/json'), [redacted valid json])` Normally this error means I'm not passing "self" as a parameter, but seeing as this method is not being called in a class, I'm not sure what to do. I've tried passing self in as a parameter in both the parameters and inside the method. And I've tried wrapping the header in brackets and parentheses. When I pass "self" I get the error message that self is undefined, and when I use the brackets instead of parentheses, I get the same error as above. Anyone with magical Python debugging skills out there? Thanks so much for taking the time to check this out! ``` def testService(name, verb, url, header="", requestBody=""): #Log out the name of the request we're testing if (name is not None) or (name.strip() is not ""): print "Checking " + name…

Accepted Answer

From the documentation, `add_header` takes two arguments. You are calling it with one argument, a tuple with two values.

What you should do:

```
req.add_header(key, value)
```

What you are currently doing because you are getting the header as a tuple:

```
req.add_header((key, value,))    # aka passing a tuple with both arguments to the key parameter
```

You need to unpack the tuple:

```
req.add_header(header[0], header[1])
```

Or even better, using the splat operator (`*`):

```
req.add_header(*header)      # Does the same thing as above
```

Also, you are using an empty string as the default argument for `header`, when when it is supplied it is a tuple. You should probably change the default value to a tuple or `None`.

add_header expecting 3 arguments instead of just key/value

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