List pull-requests filed by user.

        Params:
            username (string): filters the username of the user whose activity you are interested in.
            page (integer): the page requested. Defaults to 1.
            status (string): filter the status of pull requests. Default: Open,
                             can be Closed, Merged, All.

        Returns:
            list: A list of Pull-Requests filed by a given user for all the
                  projects for given Pagure instance.

def list_pull_requests(self, username, page, status=None):
        """
        List pull-requests filed by user.

        Params:
            username (string): filters the username of the user whose activity you are interested in.
            page (integer): the page requested. Defaults to 1.
            status (string): filter the status of pull requests. Default: Open,
                             can be Closed, Merged, All.

        Returns:
            list: A list of Pull-Requests filed by a given user for all the
                  projects for given Pagure instance.
        """
        request_url = "{}/api/0/user/{}/requests/filed".format(self.instance, username)

        payload = {}
        if username is not None:
            payload['username'] = username
        if page is not None:
            payload['page'] = page
        if status is not None:
            payload['status'] = status

        return_value = self._call_api(request_url, params=payload)

        return return_value['requests']