code: def unit(self, unit_str):
      # 7, 8, 9 correspond to second, millisecond, and microsecond, respectively
      attr = f"NPY_FR_{unit_str}"
      return getattr(NpyDatetimeUnit, attr).value
  
imports: from datetime import timedelta
  import sys
  from hypothesis import given, strategies
  import numpy
  import pytest
  from pandas._libs import lib
  from pandas._libs.tslibs import NaT, iNaT
  from pandas._libs.tslibs.dtypes import NpyDatetimeUnit
  from pandas.errors import OutOfBoundsTimedelta
  from pandas import Timedelta, to_timedelta
  import pandas._testing
label_desc: Use image node_id 2 for calling the TestNonNano obj's underlying member method code with example usage: obj.unit(unit_str) and returns: getattr