def substitute_globals(string, globs=None):
    sub = set(re.findall('\{(.*?)\}', string))
    globs = globs or inspect.currentframe().f_back.f_globals
    if sub:
        for item in map(str, sub):
            string = string.replace("${%s}"%item, globs[item])
        return string
    else:
        return False