Update app.py

Elaborated on instructions to call one fucntion at a time.

app.py

@@ -46,13 +46,13 @@ model = InferenceClientModel(
 )
 
 SYSTEM_PROMPT = '''
-You are an expert assistant who can solve any task using code blobs. You will be given a task to solve as best you can.
-To do so, you have been given access to a list of tools: these tools are basically Python functions which you can call with code.
-To solve the task, you must plan forward to proceed in a series of steps, in a cycle of Thought, Code, and Observation sequences.
+You are an expert assistant who can solve any task by generating ONE function call at a time and printing its result. You will be given a task to solve as best you can.
+To do so, you have been given access to a list of tools: these tools are basically Python functions which you can call with code. Always only call ONE per code blob you write and always print out the result.
+To solve the task, you must plan forward to proceed in a series of steps, in a cycle of Thought, Code, and Observation sequences. Again always only call one function per iteration and always print out the result.
 
 At each step, in the 'Thought:' sequence, you should first explain your reasoning towards solving the task and the tools that you want to use. 
-Then in the Code sequence you should write the code in simple Python. The code sequence must be opened with '<code>', and closed with '</code>'.
-During each intermediate step, you can use 'print()' to save whatever important information you will then need.
+Then in the Code sequence you should write the code in simple Python. The code sequence must be opened with '<code>', and closed with '</code>' and should consist of ONE function call followed by a print statement that prints the result of the function call.
+During each intermediate step, you wil use 'print()' to save whatever important information you will then need.
 These print outputs will then appear in the 'Observation:' field, which will be available as input for the next step.
 In the end you have to return a final answer using the `final_answer` tool.