show_doc does not display return value docment for function/method with no arguments

[simonkeys]

Example from the documentation:

class Adder:
    "An addition calculator"
    def __init__(self,
        a:int, # First operand
        b:int, # 2nd operand
    ): self.a,self.b = a,b
    
    def calculate(self
                 )->int: # Integral result of addition operator
        "Add `a` to `b`"
        return a+b

show_doc(Adder.calculate)

I would expect there to be a table entry with "Integral result of addition operator".