code: def _check_freqs(deltas: List[pd.Timedelta]):
      """
      Checks if all lower frequencies can be aggregated by highest frequency.
      """
      assert all(
          [d % deltas[-1] == pd.Timedelta("0H") for d in deltas]
      ), "Lower frequencies are not multiples of highest frequency."
  
imports: from typing import Iterator, List
  import numpy
  import pandas
  from gluonts.core.component import validated
  from gluonts.model.forecast import SampleForecast
  from gluonts.mx import Tensor
label_desc: Use image node_id 1 for calling a global function with example usage: _check_freqs(deltas) without return types