import argparse

def validate_options(args):

"""Validates command-line arguments."""

# Check if required argument 'input_file' is provided

if not args.input_file:

raise argparse.ArgumentError("input_file must be specified")

# Check if 'output_file' is provided, but not the same as input

if args.output_file and args.output_file == args.input_file:

raise argparse.ArgumentError("output_file must be different from input_file")

# Check if 'mode' is one of the allowed values

allowed_modes = ["read", "write", "append"]

if args.mode not in allowed_modes:

raise argparse.ArgumentError(f"mode must be one of: {', '.join(allowed_modes)}")

# Check if 'verbose' is a boolean

if not isinstance(args.verbose, bool):

raise argparse.ArgumentError("'verbose' must be a boolean") # Handle potential type errors

return args #Return the validated arguments

if __name__ == '__main__':

parser = argparse.ArgumentParser(description="Simple data processing tool.")

parser.add_argument("input_file", help="Path to the input file")

parser.add_argument("-o", "--output_file", help="Path to the output file (optional)")

parser.add_argument("-m", "--mode", choices=["read", "write", "append"], help="Operation mode")

parser.add_argument("-v", "--verbose", action="store_true", help="Enable verbose output")

args = parser.parse_args()

try:

validated_args = validate_options(args)

# Proceed with the data processing using the validated arguments

print("Arguments are valid.")

print(f"Input file: {validated_args.input_file}")

if validated_args.output_file:

print(f"Output file: {validated_args.output_file}")

print(f"Mode: {validated_args.mode}")

print(f"Verbose: {validated_args.verbose}")

except argparse.ArgumentError as e:

print(f"Error: {e}")