<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def is_timestamp(obj):
 """ Yaml either have automatically converted it to a datetime object or it is a string that will be validated later. """

    return isinstance(obj, datetime.datetime) or is_string(obj) or is_int(obj) or is_float(obj)