input: Write a python function to format and print a dictionary as a string with key-value pairs separated by commas.
  assert format_dict({'Name': 'John', 'Age': 20, 'Location': 'New York'}) == 'Name=John, Age=20, Location=New York'
  assert format_dict({'Fruit': 'Apple', 'Color': 'Red', 'Quantity': 5}) == 'Fruit=Apple, Color=Red, Quantity=5'
  assert format_dict({'Brand': 'Toyota', 'Model': 'Corolla', 'Year': 2021}) == 'Brand=Toyota, Model=Corolla, Year=2021'
output: def format_dict(d):
      return ', '.join(f'{key}={value}' for key, value in d.items())