httprunner怎么引用变量和方法

以登录为例，展示httprunner中怎么引用变量和方法。代码如下：

# NOTE: Generated By HttpRunner v3.1.6
# FROM: har\login.har

from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
from debugtalk import *


class TestCaseLogin(HttpRunner):
    config = (
        Config("登录接口")
            .base_url("xx.xx.xx.xx:xxxx")
            .verify(False)
            .export(*["cks"])
    )

    teststeps = [
        Step(
            RunRequest("/login")
            .with_variables(
                **{
                    "username": 'xx', #首次定义变量
                    "password": 'xx', #首次定义变量
                    "account": "${accountmethod($username,$password)}"  # accountmethod是debugtalk中定义的方法，通过${}引用，方法中引用变量直接$+变量名，不需要引号。单独引用变量则需要引号，看下面

                }
            )
            .post("/login")
            .with_headers(
                **{
                    "Accept": "application/json, text/javascript, */*; q=0.01",
                }
            )
            .with_data(
                {"data": "$account"} # 单独引用变量则需要引号

            )
            .validate()
            .assert_equal("status_code", 200)
            .assert_equal("body.code", 0)
            .assert_equal("body.message", "登录成功")
            .assert_equal("body.url", "/xxx"
            .assert_contains("cookies","xxx")
        ),
    ]


if __name__ == "__main__":
    TestCaseLogin().test_start()