python dictionary datetime as key, keyError

I'm trying to run a Python script using cron in Linux, which should construct a dictionary of data. I'm attempting to use datetime().now().time()as keys in the dictionary, but it seems to raise an error.

Can't the datetime type be used as a dictionary key in Python? If that is the case, what are my alternatives?

Code:

time_now = dt.datetime.now().time()
date_today = dt.datetime.now().date()
usage_dict_hourly = {}
date_wise_dict = {}

def constructing_dict(data_int):
    date_wise_dict[usage_dict_hourly[time_now]] = data_int
    print date_wise_dict

Error:

<ipython-input-9-ef6a500cc71b> in constructing_dict(data_int)
     36 
     37 def constructing_dict(data_int):
---> 38     date_wise_dict[usage_dict_hourly[time_now]] = data_int
     39     print date_wise_dict
     40 

KeyError: datetime.time(22, 40, 33, 746509)