def remove_item(self, key, value):
        """
        Remove a (key, value) pair from the dict.
        """
        existing_values = self.popall(key)
        existing_values.remove(value)

        for value in existing_values:
            self.add(key, value)

        Remove a (key, value) pair from the dict.
        
httpie/cli/dicts.py