如何解决django表单的“此字段为必填项”

<input type="text" name="field_name" required>

from django.shortcuts import render
from .forms import MyForm

def my_view(request):
    if request.method == 'POST':
        form = MyForm(request.POST)
        if form.is_valid():
            # 表单数据有效，执行相应的操作
            pass
    else:
        form = MyForm()
    return render(request, 'my_template.html', {'form': form})

from django import forms

class MyForm(forms.Form):
    field_name = forms.CharField()

    def clean_field_name(self):
        data = self.cleaned_data.get('field_name')
        if not data:
            raise forms.ValidationError("此字段为必填项")
        return data