code: def table_preview(table_name):
      
      preview = orca.get_table(table_name).to_frame().head()
      return (
          preview.to_json(orient='split', date_format='iso'),
          200,
          {'Content-Type': 'application/json'})
docs: Returns the first five rows of a table as JSON. Inlcudes all columns.
      Uses Pandas' "split" JSON format.