code: def plotly_app_identifier(name=None, slug=None, da=None, postfix=None):
      'Return a slug-friendly identifier'
  
      da, app = _locate_daapp(name, slug, da)
  
      slugified_id = app.slugified_id()
  
      if postfix:
          return "%s-%s" %(slugified_id, postfix)
      return slugified_if plotly_app_identifier(name=None, slug=None, da=None, postfix=None):
      'Return a slug-friendly identifier'
  
      da, app = _locate_daapp(name, slug, da)
  
      slugified_id = app.slugified_id()
  
      if postfix:
          return "%s-%s" %(slugified_id, postfix)
      return slugified_id
docs: Return a slug-friendly identifier