code: def _dt_to_epoch_ns(dt_series):
      """Convert a timeseries into an Int64Index of nanoseconds since the epoch.
  
      Parameters
      ----------
      dt_series : pd.Series
          The timeseries to convert.
  
      Returns
      -------
      idx : pd.Int64Index
          The index converted to nanoseconds since the epoch.
      """
      index = pd.to_datetime(dt_series.values)
      if index.tzinfo is None:
          index = index.tz_localize("UTC")
      else:
          index = index.tz_convert("UTC")
      return index.view(np.int64)
  
imports: from collections import namedtuple
  import re
  import numpy
  import pandas
  import sqlalchemy
  from toolz import first
  from zipline.errors import AssetDBVersionError
  from zipline.assets.asset_db_schema import ASSET_DB_VERSION, asset_db_table_names, asset_router, equities, equity_symbol_mappings, equity_supplementary_mappings, futures_contracts, exchanges, futures_root_symbols, metadata, version_info
  from zipline.utils.compat import ExitStack
  from zipline.utils.preprocess import preprocess
  from zipline.utils.range import from_tuple, intersecting_ranges
  from zipline.utils.sqlite_utils import coerce_string_to_eng
label_desc: Use image node_id 10 for calling a global function with example usage: _dt_to_epoch_ns(dt_series) and returns: index