#!/usr/bin/env python3
"""
Input Validation Everywhere

Source: Chapter_17_06_Case_Studies_and_Defense
Category: plugin_exploitation
"""

import argparse
import sys

def validate_email(email):
    if not isinstance(email, str):
        raise ValueError("Email must be string")
    if len(email) > 255:
        raise ValueError("Email too long")
    if not re.match(r'^[\w\.-]+@[\w\.-]+\.\w+$', email):
        raise ValueError("Invalid email format")
    return email


def main():
    """Command-line interface."""
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--verbose", "-v", action="store_true", help="Verbose output")
    args = parser.parse_args()
    
    # TODO: Add main execution logic
    pass

if __name__ == "__main__":
    main()