Can't get the required answer

can you help with this 2 question…I’ve passed all questions but not this 2…
Q1: How many countries does the dataframe contain?
Hint: Use the .shape method

Q2: Retrieve a list of continents from the dataframe?
Hint: Use the .unique method of a series.

Hints are already provided, could you show what you are trying?

continents =countries_df.continent.unique()

im using this code to answer 2 question but it shows “the value of continents is incorrect”
Error: could not JSON serialize output

This seems to be correct, Probably you are resetting the value of continents somewhere afterwards. Please don’t change the value of the variable continents.