old_contents: 
  from django import forms
  from django.forms import ModelForm
  from django.forms.models import inlineformset_factory
  
  from common.models import Repository, Collaboration
  
  slug_errors = {
          'invalid' : "Use only letters, numbers, underscores, and hyphens",
  }
  
  class NewRepositoryForm(forms.Form):
      repo_name = forms.SlugField(max_length=100, error_messages=slug_errors)
  
  
  class RepositoryForm(ModelForm):
      class Meta:
          model = Repository
          fields = ['description', 'long_description', 'is_public']
  
  
  CollaborationFormSet = inlineformset_factory(Repository, Repository.collaborators.through, exclude=('repository'))
  
new_contents: 
  from django import forms
  from django.forms import ModelForm
  from django.forms.models import inlineformset_factory
  
  from common.models import Repository
  
  slug_errors = {
          'invalid' : "Use only letters, numbers, underscores, and hyphens",
  }
  
  class NewRepositoryForm(forms.Form):
      repo_name = forms.SlugField(max_length=100, error_messages=slug_errors)
  
  
  class RepositoryForm(ModelForm):
      class Meta:
          model = Repository
          fields = ['description', 'long_description', 'is_public']
  
  
  CollaborationFormSet = inlineformset_factory(Repository, Repository.collaborators.through, exclude=('repository'))
  
  
subject: Remove unused import