old_contents: from django import forms
  
  from main.fields import RegexField
  
  
  class IndexForm(forms.Form):
      id_list = forms.CharField(
          widget=forms.Textarea, label='ID List',
          help_text='List of students IDs to query, one per line.')
      student_id_regex = RegexField(
          label='Student ID regex',
          help_text='Regular expression used to match the student ID in each '
                    'line. If cannot match (or a student is not found in the '
                    'database), then the line is left as is.',
          initial=r'\b\d{7,}\b',
          widget=forms.TextInput(attrs={'placeholder': r'\b\d{7,}\b'}))
  
new_contents: from django import forms
  
  from main.fields import RegexField
  
  
  class IndexForm(forms.Form):
      id_list = forms.CharField(
          help_text='List of students IDs to query, one per line.',
          label='ID List',
          widget=forms.Textarea(attrs={
              'placeholder': 'Random text\n1234567\n7654321'}))
      student_id_regex = RegexField(
          label='Student ID regex',
          help_text='Regular expression used to match the student ID in each '
                    'line. If cannot match (or a student is not found in the '
                    'database), then the line is left as is.',
          initial=r'\b\d{7,}\b',
          widget=forms.TextInput(attrs={'placeholder': r'\b\d{7,}\b'}))
  
subject: Add placeholder to ID list field