code: def test_locate(self):
      self.assertEqual(self.quantiles.locate(25), 2)
      self.assertEqual(self.quantiles.locate(40), 4)
  
      with self.assertRaises(ValueError):
          self.quantiles.locate(-10)
  
      with self.assertRaises(ValueError):
          self.quantiles.locate(51)
  
file_path: agate/tests/test_utils.py
imports: import unittest
  from decimal import Decimal
  from agate.utils import Quantiles, letter_name, round_limits
label_desc: Use image node_id 3 for calling the TestQuantiles obj's underlying member method code with example usage: obj.test_locate() without return types