old_contents: from django.core.checks import Tags, Warning, register
  
  
  @register(Tags.compatibility)
  def pagination_system_check(app_configs, **kwargs):
      errors = []
      # Use of default page size setting requires a default Paginator class
      from rest_framework.settings import api_settings
      if api_settings.PAGE_SIZE and not api_settings.DEFAULT_PAGINATION_CLASS:
          errors.append(
              Warning(
                  "You have specified a default PAGE_SIZE pagination rest_framework setting,"
                  "without specifying also a DEFAULT_PAGINATION_CLASS.",
                  hint="The default for DEFAULT_PAGINATION_CLASS is None. "
                       "In previous versions this was PageNumberPagination. "
                       "If you wish to define PAGE_SIZE globally whilst defining "
                       "pagination_class on a per-view basis you may silence this check.",
                  id="rest_framework.W001"
              )
          )
      return errors
  
new_contents: from django.core.checks import Tags, Warning, register
  
  
  @register(Tags.compatibility)
  def pagination_system_check(app_configs, **kwargs):
      errors = []
      # Use of default page size setting requires a default Paginator class
      from rest_framework.settings import api_settings
      if api_settings.PAGE_SIZE and not api_settings.DEFAULT_PAGINATION_CLASS:
          errors.append(
              Warning(
                  "You have specified a default PAGE_SIZE pagination rest_framework setting, "
                  "without specifying also a DEFAULT_PAGINATION_CLASS.",
                  hint="The default for DEFAULT_PAGINATION_CLASS is None. "
                       "In previous versions this was PageNumberPagination. "
                       "If you wish to define PAGE_SIZE globally whilst defining "
                       "pagination_class on a per-view basis you may silence this check.",
                  id="rest_framework.W001"
              )
          )
      return errors
  
subject: Fix punctuation in system check (#7281)