code: def _timestamp_proto_to_float(ts):
      """Converts `timestamp_pb2.Timestamp` to float seconds since epoch."""
      return ts.ToNanoseconds() / 1e9
  
imports: import collections
  import contextlib
  import grpc
  from tensorboard.util import tensor_util
  from tensorboard.util import timing
  from tensorboard import errors
  from tensorboard.data import provider
  from tensorboard.data.proto import data_provider_pb2
  from tensorboard.data.proto import data_provider_pb2_grpc
label_desc: Use image node_id 4 for calling a global function with example usage: _timestamp_proto_to_float(ts) and returns: unknown