#This demonstrates a simple "Eureka" traversal to find a character in
# a string. It accepts an optional parameter which is the  starting position.
def find(aStr, aChr, startAt = 0 ):

    index = startAt

    while index < len(aStr):
        
        letter = aStr[index]
        
        if letter == aChr:
            return index
    
        index = index + 1
        
    return None