def weave(str1, str2, wString='', i=0):
    weavedString=wString
    if str1 == "" or str2 == "":
        #If either is empty, it returns empty
        return ""
    if len(str1) == i:
        #If the first string has no more room, it adds the rest
        #of the second to the weave
        weavedString=weavedString+str2[i:]
        return weavedString
    if len(str2) == i:
        #Same as above, but the other way around
        weavedString=weavedString+str1[i:]
        return weavedString
    weavedString=weavedString+str1[i]+str2[i]
    weave(str1, str2, weavedString)

weave("Hello", "Shalom")