how to give class for django form.forms code example

Example 1: django forms set class

class UserLoginForm(forms.Form):
    username = forms.CharField(widget=forms.TextInput(
        attrs={
        'class':'form-control',
        'placeholder':'Username'
        }
    ))
    password = forms.CharField(widget=forms.PasswordInput(
        attrs={
        'class':'form-control',
        'placeholder':'Password'
        }
    ))

Example 2: django form field class

subject = forms.CharField(label='subject', max_length=100 , widget=forms.TextInput(attrs={'class': "form-control"}))