code: def test_median(pd_es):
      f = Feature(
          pd_es["log"].ww["value_many_nans"],
          parent_dataframe_name="customers",
          primitive=Median,
      )
      fm = calculate_feature_matrix(
          [f],
          entityset=pd_es,
          instance_ids=[0, 1, 2],
          cutoff_time=datetime(2015, 6, 8),
      )
  
      correct = [1, 3, np.nan]
      np.testing.assert_equal(fm[f.get_name()].values, correct)
  
imports: from datetime import datetime
  from inspect import isclass
  from math import isnan
  import numpy
  import pandas
  import pytest
  from woodwork.column_schema import ColumnSchema
  from woodwork.logical_types import Datetime
  from featuretools import AggregationFeature, Feature, IdentityFeature, Timedelta, calculate_feature_matrix, dfs, primitives
  from featuretools.entityset.relationship import RelationshipPath
  from featuretools.feature_base.cache import feature_cache
  from featuretools.primitives import Count, Max, Mean, Median, NMostCommon, NumTrue, NumUnique, Sum, TimeSinceFirst, TimeSinceLast, get_aggregation_primitives
  from featuretools.primitives.base import AggregationPrimitive
  from featuretools.synthesis.deep_feature_synthesis import DeepFeatureSynthesis, match
  from featuretools.tests.testing_utils import backward_path, feature_with_name, to_pandas
  from featuretools.utils.gen_utils import Library
label_desc: Use image node_id 17 for calling a global function with example usage: test_median(pd_es) without return types