input: Write a function to modify the given Python code to handle errors. The function should attempt to read data from a JSON file and return the data. If the file does not exist, it should print "The file specified does not exist." If the file is not valid JSON, it should print "The file specified is not in a valid JSON format."
  
  
  def read_data_from_json(filename):
      try:
          with open(filename, 'r') as f:
              data = json.load(f)
          return data
      except FileNotFoundError:
          print("The file specified does not exist.")
      except json.decoder.JSONDecodeError:
          print("The file specified is not in a valid JSON format.")
  
  
  assert read_data_from_json("existing_file.json") == {"key": "value"}
  assert read_data_from_json("nonexistent_file.json") == None
  assert read_data_from_json("invalid_json_file.json") == None
output: def read_data_from_json(filename):
      try:
          with open(filename, 'r') as f:
              data = json.load(f)
          return data
      except FileNotFoundError:
          print("The file specified does not exist.")
      except json.decoder.JSONDecodeError:
          print("The file specified is not in a valid JSON format.")