message: [bugfix] iframe and markup are broken
  fixes
diff: @@ -262,7 +262,7 @@ class BaseViz(object):
  df = self.get_df()
  if not self.error_message:
  data = self.get_data(df)
  - rowcount = len(df.index)
  + rowcount = len(df.index) if df is not None else 0
  except Exception as e:
  logging.exception(e)
  if not self.error_message:
  @@ -523,7 +523,7 @@ class MarkupViz(BaseViz):
  is_timeseries = False
  def get_df(self):
  - return True
  + return None
  def get_data(self, df):
  markup_type = self.form_data.get('markup_type')
  