Check if some functional programming method could be used to group posts by tags

[mhgbrg]

This is the code block that should be reworked:

all_tags = {}
for post in posts:
    try:
        tags = post['tags']
        for tag in tags:
            if tag not in all_tags:
                all_tags[tag] = []
            all_tags[tag].append(post)
    except KeyError:
        # Post has no tags.
        pass