code: def _merge_params(base, overwrite):
      """Merges two dictionaries when values from ``overwrite`` takes precedence over values of ``base`` dictionary.
  
      Both input parameters are not modified.
  
      :param base: A dictionary
      :param overwrite: A dictionary. If a value with the same key exists in ``base``, it is overwritten by the value from
        this dictionary.
      :return: A combined dictionary
      """
      # Create a shallow copy of base
      combined = copy(base)
      combined.update(overwrite)
      return combined
  
file_path: petastorm/petastorm/tests/test_tf_dataset.py
imports: import functools
  import operator
  from copy import copy
  import numpy
  import pytest
  import tensorflow.compat.v1
  from petastorm import make_reader, make_batch_reader
  from petastorm.ngram import NGram
  from petastorm.predicates import in_lambda
  from petastorm.tests.test_common import TestSchema
  from petastorm.tests.test_tf_utils import create_tf_graph
  from petastorm.tf_utils import make_petastorm_dataset
label_desc: Use image node_id 1 for calling a global function with example usage: _merge_params(base, overwrite) and returns: combined