Returns the function's return (type, value) tuples.
Example
from glider import *
def query():
# Fetch a list of functions
functions = Functions().exec(1,4)
for func in functions:
# Retrieve the return instructions of the first function
return_tuple = func.return_tuple()
print(f"Type is - {return_tuple[0]}")
for value in return_tuple[1]:
print(value.expression)
return functions
