Django自定义类与视图开发遇属性/类型错误，求解决方向

问题背景 #

我创建了以下自定义类，尝试在Django视图中输出其内容，但持续遇到各类AttributeError和TypeError，恳请指点解决方向。

原自定义类代码 #

from pickle import OBJ
from urllib.request import HTTPPasswordMgr
from django.shortcuts import render
from django.http import request

class Bloodcancer():

    def __init__(self, my_symptoms=None, my_causes=None, my_treatments=None):
        self.symptoms = my_symptoms
        self.causes = my_causes
        self.treatments = my_treatments

class AcuteMyeloidLeukemia(Bloodcancer):

    def my_symptoms():
        symptomatology = {
            tuple({'a': "pale appearance",'b': "weakness or feeling tired", 'c': "shortness of breath", 'd': "easy brusing or bleeding",'e': "petechiae which are flat, pinpoint spots under the skin caused by bleeding", 'f': "loss of weight", 'g': "loss of appetite", 'h': "fever", 'i': "frequent minor infection"}
            )
            }
        print (symptomatology)

    def my_causes(self):
        causes = ['age', 'being male', 'genes', 'environment', 'other bone marrow diseases']
        return render(request, 'Healthcare/Conditions/Blood/Causes.html', {{causes}})

    def my_treatments(self):
        treatments = ['induction therapy', 'consolidation therapy', 'chemotherapy', 'allogenic stem cell transplantation', 'central nervous system treatment', 'treatment of older and frail patients with AML', 'Treatment of refractory or relapsed AML', 'Supportive treatment']
        return render(request, 'Healthcare/Conditions/Blood/Treatments.html', {{treatments}})

原views.py代码 #

from django.shortcuts import render
from django.http import HttpResponseBadRequest, request
from django.urls import path
from Healthcare.Conditions.Blood.blood import AcuteMyeloidLeukemia as a

def symptoms_view(self):
    sample_set = a.my_symptoms()
    x = sample_set['b'].get()
    return render('Symptoms.html', {xx})

原urls.py代码 #

from datetime import datetime
from django.urls import path
from django.contrib import admin
from django.contrib.auth.views import LoginView, LogoutView
from Healthcare import views


urlpatterns = [
    path('admin/', admin.site.urls),
    path('Healthcare/Conditions/Blood/Symptoms/', views.symptoms_view)
]

错误分析与修正方案 #

1. 类方法基础错误

• AcuteMyeloidLeukemia.my_symptoms 缺少self参数（实例方法必须包含该参数），且没有返回值，同时错误地用tuple()包裹字典创建了无效的键值结构。
• 类方法中不能直接导入request，render的第一个参数必须是视图传递过来的请求对象。
• 模板上下文传递错误：{{causes}}是无效语法，需用{'key': value}的标准字典格式。

2. 视图函数错误

• Django视图函数第一个参数必须是request（请求对象），而非self。
• 调用类的实例方法前，必须先实例化类。
• render函数的正确参数顺序是：render(request, 模板路径, 上下文字典)，原代码缺少request参数，且{xx}是无效的上下文写法。

3. 冗余导入清理

• 自定义类中pickle.OBJ、urllib.request.HTTPPasswordMgr属于无用导入，应删除。

修正后的代码 #

自定义类（blood.py）

from django.shortcuts import render

class Bloodcancer():
    def __init__(self, my_symptoms=None, my_causes=None, my_treatments=None):
        self.symptoms = my_symptoms
        self.causes = my_causes
        self.treatments = my_treatments

class AcuteMyeloidLeukemia(Bloodcancer):
    def my_symptoms(self):
        # 直接返回正常字典结构，无需tuple包裹
        symptomatology = {
            "a": "pale appearance",
            "b": "weakness or feeling tired",
            "c": "shortness of breath",
            "d": "easy brusing or bleeding",
            "e": "petechiae which are flat, pinpoint spots under the skin caused by bleeding",
            "f": "loss of weight",
            "g": "loss of appetite",
            "h": "fever",
            "i": "frequent minor infection"
        }
        return symptomatology

    def my_causes(self):
        return ['age', 'being male', 'genes', 'environment', 'other bone marrow diseases']

    def my_treatments(self):
        return ['induction therapy', 'consolidation therapy', 'chemotherapy', 'allogenic stem cell transplantation', 'central nervous system treatment', 'treatment of older and frail patients with AML', 'Treatment of refractory or relapsed AML', 'Supportive treatment']

views.py

from django.shortcuts import render
from Healthcare.Conditions.Blood.blood import AcuteMyeloidLeukemia

def symptoms_view(request):
    # 先实例化类
    aml_instance = AcuteMyeloidLeukemia()
    sample_set = aml_instance.my_symptoms()
    # 直接通过键获取值，若要处理键不存在的情况可改用get()
    x = sample_set['b']
    # 上下文用字典传递，键为模板中要使用的变量名
    return render(request, 'Healthcare/Conditions/Blood/Symptoms.html', {'symptom_b': x, 'all_symptoms': sample_set})

# 新增病因、治疗视图（按需使用）
def causes_view(request):
    aml_instance = AcuteMyeloidLeukemia()
    causes = aml_instance.my_causes()
    return render(request, 'Healthcare/Conditions/Blood/Causes.html', {'causes': causes})

def treatments_view(request):
    aml_instance = AcuteMyeloidLeukemia()
    treatments = aml_instance.my_treatments()
    return render(request, 'Healthcare/Conditions/Blood/Treatments.html', {'treatments': treatments})

urls.py

from django.urls import path
from django.contrib import admin
from django.contrib.auth.views import LoginView, LogoutView
from Healthcare import views

urlpatterns = [
    path('admin/', admin.site.urls),
    path('Healthcare/Conditions/Blood/Symptoms/', views.symptoms_view),
    # 添加病因、治疗页面的路由
    path('Healthcare/Conditions/Blood/Causes/', views.causes_view),
    path('Healthcare/Conditions/Blood/Treatments/', views.treatments_view),
]

内容的提问来源于stack exchange，提问作者Neil Faulkner