How do I get CAS to evaluate a Python-in-CAS function? (Solved)

[StephenG1CMZ]

How do I get this function to evaluate...
All I get is the name of the function returned
(The Python string syntax may need correcting too

Code:


CAS file: 
#cas
HAMMINGCAS():=
BEGIN
def hammingdistance(s1, s2) -> int:
    """Return the Hamming distance between equal-length sequences."""
    if len(s1) != len(s2):
        raise ValueError("Undefined for sequences of unequal length.")
    count = 0
    for ii in s1
     el1 = s1(ii)
     el2 = s2(ii)
     if el1 != el2:
      count = count+1
    return count

    """return sum(el1 != el2 for el1, el2 in zip(s1, s2)) """
END;
#end

PPL file:

 EXPORT TRY()
 BEGIN
  LOCAL ST1:="AB";
  LOCAL ST2:="AB";
  RETURN CAS("eval(hammingdist(ST1,ST2))");
 END;

EXPORT HAMMING()
BEGIN
  //def hamming_distance(s1, s2) -> int:
  // """Return the Hamming distance between equal-length sequences."""
  //  if len(s1) != len(s2):
  //      raise ValueError("Undefined for sequences of unequal length.")
  //  return sum(el1 != el2 for el1, el2 in zip(s1, s2))
END;