CodeGen

# Python Function for Data Processing

```python
import pandas as pd
from typing import Dict, List, Optional

def process_data(input_file: str, output_format: str = 'json') -> Optional[Dict[str, List]]:
    """
    Processes data from a CSV file and returns it in the specified format.

    Args:
        input_file (str): Path to the input CSV file.
        output_format (str): Desired output format ('json' or 'csv'). Default is 'json'.

    Returns:
        Optional[Dict[str, List]]: Processed data in the specified format or None if an error occurs.
    """
    try:
        # Read the CSV file
        df = pd.read_csv(input_file)

        # Validate input data
        if df.empty:
            raise ValueError("Input file is empty")

        # Process data
        processed_data = {
            'columns': df.columns.tolist(),
            'data': df.values.tolist()
        }

        # Return data in the specified format
        if output_format.lower() == 'json':
            return processed_data
        elif output_format.lower() == 'csv':
            return pd.DataFrame(processed_data['data'], columns=processed_data['columns']).to_csv(index=False)
        else:
            raise ValueError("Unsupported output format")

    except Exception as e:
        print(f"Error processing data: {e}")
        return None

# Example usage
if __name__ == "__main__":
    result = process_data('input_data.csv', 'json')
    print(result)
```