Unexpected Error using the parse_args () function of the ArgumentParser object in Python

In a simple code I'm doing in Python, I get the exception below, when I call the function parser_args() on the object of type ArgumentParser :

Unexpected error: (<type 'exceptions.SystemExit'>, SystemExit(0,), <traceback object at 0x10c97fdd0>)

At the end I added the full tracer.

I started writing the code now, based on the template offered by Eclipse Mars.1 plus its the PyDev plugin, and there is nothing else besides the code below:

#!/usr/local/bin/python2.7
# encoding: utf-8
'''
br.com.cdcp.python.client -- Um Cliente TCP para comprovação de conhecimentos em programação Python

br.com.cdcp.python.client faz conexão com um sevidor que receber uma mensagem TCP,
aguarda a confirmação do envio, e armazena o token para uso futuro.

@author:     Carlos Delfino

@copyright:  2015, cdcp. All rights reserved.

@license:    GNU

@contact:    [email protected]
@deffield    updated: Updated
'''

import sys
import os

from argparse import ArgumentParser
from argparse import RawDescriptionHelpFormatter

__all__ = []
__version__ = 0.1
__date__ = '2015-11-17'
__updated__ = '2015-11-17'

DEBUG = 1
TESTRUN = 0
PROFILE = 0

class CLIError(Exception):
    '''Generic exception to raise and log different fatal errors.'''
    def __init__(self, msg):
        super(CLIError).__init__(type(self))
        self.msg = "E: %s" % msg
    def __str__(self):
        return self.msg
    def __unicode__(self):
        return self.msg


def main(argv=None): # IGNORE:C0111
    '''Opções da Linha de Comando.'''

    if argv is None:
        argv = sys.argv
    else:
        sys.argv.extend(argv)

    program_name = os.path.basename(sys.argv[0])
    program_version = "v%s" % __version__
    program_build_date = str(__updated__)
    program_version_message = '%%(prog)s %s (%s)' % (program_version, program_build_date)
    program_shortdesc = __import__('__main__').__doc__.split("\n")[1]
    program_license = '''%s

  Created by Carlos Delfino on %s.
  Copyright 2015 cdcp. All rights reserved.

  GNU - Versão 3.0

  Distributed on an "AS IS" basis without warranties
  or conditions of any kind, either express or implied.

USAGE
''' % (program_shortdesc, str(__date__))

    try:
        # Setup argument parser
        parser = ArgumentParser(
                                description=program_license,
                                formatter_class=RawDescriptionHelpFormatter)
        parser.add_argument('-s', '--server',
                            action="store",
                            required = False)
        parser.add_argument('-p', '--port',
                            action="store",
                            required = False)
        #parser.add_argument('-v', '--version',
        #                    action='version',
        #                    version=program_version_message)

        # Process arguments
        args = parser.parse_args()

        server = args.server
        port = args.port

        msg = '''
Servidor Selecionado: %s
Porta a ser usada: %s
''' % (server,port)
        sys.stdout.write(msg)

        return 0
    except KeyboardInterrupt:
        ### handle keyboard interrupt ###
        return 0
    except Exception as e:
        if DEBUG or TESTRUN:
            raise(e)
        indent = len(program_name) * " "
        sys.stderr.write(program_name + ": " + repr(e) + "\n")
        sys.stderr.write(indent + " use --help para obter ajuda.")
        return 2
    except:
        print "Unexpected error:", sys.exc_info()
        raise

if __name__ == "__main__":
    if DEBUG:
        sys.argv.append("-h")
    if TESTRUN:
        import doctest
        doctest.testmod()
    if PROFILE:
        import cProfile
        import pstats
        profile_filename = 'br.com.cdcp.python.client_profile.txt'
        cProfile.run('main()', profile_filename)
        statsfile = open("profile_stats.txt", "wb")
        p = pstats.Stats(profile_filename, stream=statsfile)
        stats = p.strip_dirs().sort_stats('cumulative')
        stats.print_stats()
        statsfile.close()
        sys.exit(0)

    sys.exit(main())

I'm using Python 2.7 on a Mac with El Capitain.

I've tried both Eclipse Mars.1, the Python console, and the command line by running the file directly.

Below is the complete tracer:

Traceback (most recent call last):
  File "/Users/extracbd/workspace/cdcp/workspace-entrevista-carlos-delfino/Client-Python/src/br/com/cdcp/python/client.py", line 197, in <module>
    exitCode = main()
  File "/Users/extracbd/workspace/cdcp/workspace-entrevista-carlos-delfino/Client-Python/src/br/com/cdcp/python/client.py", line 134, in main
    args = parseArgs(argv)
  File "/Users/extracbd/workspace/cdcp/workspace-entrevista-carlos-delfino/Client-Python/src/br/com/cdcp/python/client.py", line 95, in parseArgs
    args = parser.parse_args()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/argparse.py", line 1701, in parse_args
    args, argv = self.parse_known_args(args, namespace)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/argparse.py", line 1733, in parse_known_args
    namespace, args = self._parse_known_args(args, namespace)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/argparse.py", line 1939, in _parse_known_args
    start_index = consume_optional(start_index)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/argparse.py", line 1879, in consume_optional
    take_action(action, args, option_string)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/argparse.py", line 1807, in take_action
    action(self, namespace, argument_values, option_string)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/argparse.py", line 997, in __call__
    parser.exit()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/argparse.py", line 2362, in exit
    _sys.exit(status)
SystemExit: 0