input: Write a python function to read a JSON file and return its content as a dictionary.
  assert read_json_file('article_data.json') == {'name': 'Bob Dylan', 'prize': 'Nobel Prize for Literature', 'year': 2016, 'description': 'having created new poetic expressions within the great American song tradition'}
  assert read_json_file('empty_file.json') == {}
output: def read_json_file(filename):
      import json
      with open(filename, 'r') as file:
          return json.load(file)