code: def combine_dicts(new_dict, old_dict):
      
      old_data_keys = list(old_dict.keys())
      new_data_keys = list(new_dict.keys())
      all_keys = set(old_data_keys).union(new_data_keys)
      combined_data_dict = {}
      for k in all_keys:
          try:
              combined_data_dict[k] = new_dict[k]
          except KeyError:
              combined_data_dict[k] = old_dict[k]
      return combined_data_dict
docs: returns a dictionary with all key, value pairs from new_dict.
      also returns key, value pairs from old_dict, if that key does not exist in new_dict.
      if a key is present in both new_dict and old_dict, the new_dict value will take precedence.