import re


def separate_camel_case(sentence):
    """
    Convert instances of 'a wordThen another' to 'a word Then another'
    """
    for i in reversed(list(re.finditer(r"[a-z][A-Z][a-z]", sentence))):
        sentence = sentence[: (i.start() + 1)] + " " + sentence[(i.end() - 2) :]
    return sentence