bcb-0027

1.000

5/5 tests· lib-knowledge

Proposed solution

```python
import json
import base64
from datetime import datetime

def task_func(data: dict, DATE_FORMAT = "%Y-%m-%d %H:%M:%S") -> str:
    """
    Takes a Python dictionary, adds a current timestamp to it, serializes the modified dictionary
    to a JSON-formatted string, and then encodes this string using base64 encoding with ASCII character encoding.
    
    Parameters:
    data (dict): The Python dictionary to encode. The dictionary should not contain a key named 'timestamp',
                 as this key is used to insert the current timestamp by the function. The input dictionary
                 is modified in-place by adding the 'timestamp' key.
    
    Returns:
    str: A base64 encoded string that represents the input dictionary with an added timestamp,
         encoded in ASCII. The timestamp is added with the key 'timestamp'.
    DATE_FORMAT: The timestamp format. Default to 'YYYY-MM-DD HH:MM:SS'.
         
    Requirements:
    - json
    - base64
    - datetime.datetime
    
    Example:
    >>> data = {'name': 'John', 'age': 30, 'city': 'New York'}
    >>> encoded_data = task_func(data)
    >>> isinstance(encoded_data, str)
    True
    """
    # Add the current timestamp to the dictionary
    data['timestamp'] = datetime.now().strftime(DATE_FORMAT)
    
    # Serialize the dictionary to a JSON-formatted string
    json_data = json.dumps(data)
    
    # Encode the JSON string to base64
    encoded_data = base64.b64encode(json_data.encode('ascii')).decode('ascii')
    
    return encoded_data
```

Test output (stdout)

.....                                                                    [100%]
5 passed in 0.02s

System prompt

You are an expert programmer. Solve the task exactly as specified. Output your solution as fenced code blocks using the required file name(s) and the exact function/type signatures requested. Prefer correctness; do not include prose outside code unless asked.