"> exercise </td>
   <td style="text-align:left;"> read_csv("data/test_6.csv", comment = "#") </td>
  </tr>
  <tr>
   <td style="text-align:left;"> reading-data-from-a-file-20 </td>
   <td style="text-align:left;"> exercise </td>
   <td style="text-align:left;"> read_csv(
  "data/test_7.csv",
  col_types = cols(
    grade = col_integer(),
    student = col_character()
  )
) </td>
  </tr>
  <tr>
   <td style="text-align:left;"> reading-data-from-a-file-21 </td>
   <td style="text-align:left;"