feat(curriculum): Added an additional test in the python challenge (#57854)

Co-authored-by: Dario-DC <105294544+Dario-DC@users.noreply.github.com>
Co-authored-by: Naomi <accounts+github@nhcarrigan.com>

curriculum/challenges/english/07-scientific-computing-with-python/learn-interfaces-by-building-an-equation-solver/66793c5b4bdacc17c40ff8e7.md

@@ -13,6 +13,16 @@ From now on, you'll keep building the output by concatenating strings to `output
 
 Create a string containing the string representation of your equation centered in a width of `24` characters. Make the string begin and end with two newline characters, and add your new string to the current value of `output_string`.
 
+The output of the `solver` function should look like this:
+
+```md
+
+----Linear Equation-----
+
+       2x +3 = 0        
+
+```
+
 # --hints--
 
 The `solver` function should return a different string.
@@ -30,6 +40,15 @@ assert solver(eq) == expected
 `) })
 ```
 
+You should use the conversion flag `!s` to convert `equation` into a string.
+
+```js
+({ test: () => (runPython(`
+function = str(_Node(_code).find_function("solver"))
+assert "equation!s" in function
+`)) })
+```
+
 # --seed--
 
 ## --seed-contents--