def isprintable(instring):
    #http://stackoverflow.com/a/3637294
    import string
    printset = set(string.printable)
    isprintable = set(instring).issubset(printset)
    return isprintable

def count_newlines_from_end(str):
    i = len(str)
    while i > 0:
        if str[i-1] != '\n':
            break
        i -= 1
    return len(str) - i