>>> from google.protobuf.timestamp_pb2 import Timestamp
>>> from google.cloud.bigtable._generated.bigtable_instance_admin_pb2 import (
...     CreateInstanceMetadata)
>>>
>>> metadata1 = CreateInstanceMetadata(request_time=Timestamp(nanos=100))
>>> metadata2 = CreateInstanceMetadata(request_time=Timestamp(nanos=100))
>>> t = Timestamp(seconds=1000)
>>> metadata1
request_time {
  nanos: 100
}

>>> metadata2
request_time {
  nanos: 100
}

>>> t
seconds: 1000

>>>
>>> metadata1.request_time.MergeFrom(t)
>>> metadata2.request_time.CopyFrom(t)
>>>
>>> metadata1
request_time {
  seconds: 1000
  nanos: 100
}

>>> metadata2
request_time {
  seconds: 1000
}