def add_contents(self, contents=[]):
    if isinstance(contents, str):
        self.contents.append(contents)
        return
    for c in contents:
        if isinstance(c, str):
            self.contents.append(c)
        else:
            for c2 in c:
                if isinstance(c2, str):
                    self.contents.append(c2)
        self.contents.append('\n')
def add_contents(self, contents=[]):
    if isinstance(contents, str):
        self.contents.append(contents)
        return
    for c in contents:
        if isinstance(c, str):
            self.contents.append(c)
        else:
            for c2 in c:
                if isinstance(c2, str):
                    self.contents.append(c2)
        self.contents.append('\n')