input: Write a python function to extract and return all items from both 'Fruits' and 'Vegetables' lists in a single list.
  assert extract_items(data) == ['Apple', 'Banana', 'Orange', 'Carrot', 'Cucumber', 'Potato']
  assert extract_items({'Fruits': ['Mango'], 'Vegetables': ['Spinach']}) == ['Mango', 'Spinach']
  assert extract_items({'Fruits': [], 'Vegetables': ['Tomato']}) == ['Tomato']
output: def extract_items(data):
      return data.get('Fruits', []) + data.get('Vegetables', [])