input: from typing import Dict
  
  def read_data_from_json(filename: str) -> Dict:
      """ Reads data from a JSON file and returns it as a dictionary. If the file does not exist, 
      an error message is printed. If the file is not in a valid JSON format, another error message is printed.
      >>> read_data_from_json('example.json')
      {'key': 'value'}
      >>> read_data_from_json('nonexistent_file.json')
      The file specified does not exist.
      >>> read_data_from_json('invalid_format.json')
      The file specified is not in a valid JSON format.
      """
output:     import json
      import os
  
      if not os.path.exists(filename):
          print("The file specified does not exist.")
          return None
  
      try:
          with open(filename, 'r') as file:
              data = json.load(file)
              return data
      except json.JSONDecodeError:
          print("The file specified is not in a valid JSON format.")
          return None