def __init__(self, api_url, username, password):
self.api_url = api_url<EOL>self.username = username<EOL>self.password = password<EOL>self.generate_token()<EOL>
Make request in API to generate a token.

        :param api_url: URL of API
        :param username: username of API
        :param password: password of API
        :raises ValidationError: if API returns status 400
        :raises Unauthorized: if API returns status 401
        :raises ApiError: if API returns other status