以下是一个示例代码，展示如何按照开始和结束时间对事件进行分组：

from operator import itemgetter
from itertools import groupby

# 定义事件列表，每个事件包含开始时间和结束时间
events = [
    {"start": "2022-01-01 09:00", "end": "2022-01-01 10:00", "name": "Event 1"},
    {"start": "2022-01-01 10:30", "end": "2022-01-01 11:30", "name": "Event 2"},
    {"start": "2022-01-01 09:30", "end": "2022-01-01 12:00", "name": "Event 3"},
    {"start": "2022-01-01 13:00", "end": "2022-01-01 14:00", "name": "Event 4"},
    {"start": "2022-01-01 14:30", "end": "2022-01-01 15:30", "name": "Event 5"},
    {"start": "2022-01-01 14:00", "end": "2022-01-01 16:00", "name": "Event 6"}
]

# 按开始时间对事件列表进行排序
events.sort(key=itemgetter("start"))

# 使用groupby函数按开始时间分组事件
grouped_events = groupby(events, key=itemgetter("start"))

# 遍历分组后的事件
for start_time, group in grouped_events:
    print(f"Events starting at {start_time}:")
    for event in group:
        print(event["name"])
    print()

运行上述代码，将输出按开始时间分组后的事件列表：

Events starting at 2022-01-01 09:00:
Event 1

Events starting at 2022-01-01 09:30:
Event 3

Events starting at 2022-01-01 10:30:
Event 2

Events starting at 2022-01-01 13:00:
Event 4

Events starting at 2022-01-01 14:00:
Event 6

Events starting at 2022-01-01 14:30:
Event 5

以上代码首先通过sort函数按照开始时间对事件列表进行排序。然后使用groupby函数对排序后的事件列表进行分组，其中key参数指定按照开始时间进行分组。最后，输出每个分组的开始时间和对应的事件名称。