Added enum type in the parser file

added enum type with the aim to use a circuit-breaker logic implemented
by the argparser itself, with a fail-fast behavior when trying to cast
the input parameters with values different than the ones expected.

Test Plan:
PASS: Run install_vbox.py with expected values for modified parameters

Failure Path:
PASS: Run install_vbox.py with non-expected values fails right away

Task: 47907
Story: 2005051
Change-Id: I30d283947200019d2472a7fdd8804026db924155
Signed-off-by: Tomás Barros <tomas.barros@encora.com>
Signed-off-by: Bruno Muniz <bruno.muniz@encora.com>

virtualbox/pybox/Parser.py

@@ -1,5 +1,5 @@
 # pylint: disable=invalid-name
-#!/usr/bin/python3
+# !/usr/bin/python3
 #
 # SPDX-License-Identifier: Apache-2.0
 #
@@ -7,10 +7,56 @@
 """
 Parser to handle command line arguments
 """
+
 import argparse
 import re
 from argparse import ArgumentParser, RawTextHelpFormatter
 import getpass
+from enum import Enum
+
+
+class StringEnum(Enum):
+    """This class aims to serve as a parent class for a parser
+    type checker"""
+
+    @classmethod
+    def get_members_values(cls):
+        """Static method that returns a list of enum members values"""
+        return [v.value for v in cls.__members__.values()]
+
+
+class SetupType(StringEnum):
+    """Class aimed to help parser choose between installation
+    predefined types"""
+
+    AIO_SX = 'AIO-SX'
+    AIO_DX = 'AIO-DX'
+    STANDARD = 'STANDARD'
+    STORAGE = 'STORAGE'
+
+
+class VboxNetworkType(StringEnum):
+    """Class aimed to help parser choose between virtual box
+    network types"""
+
+    HOST_ONLY = 'hostonly'
+    NAT = 'nat'
+
+
+class SecurityProfile(StringEnum):
+    """Class aimed to help parser choose between
+    security profile types"""
+
+    STANDARD = 'standard'
+    EXTENDED = 'extended'
+
+
+class LabInstallationType(StringEnum):
+    """Class aimed to help parser choose between
+    lab installation types"""
+
+    GRAPHICAL = 'graphical'
+    SERIAL = 'serial'
 
 
 def validate_password(pwd: str):
@@ -55,16 +101,9 @@ def parse_setup_config(parser: ArgumentParser):
     """
     Mutate parser with CLI arguments related to the setup type
     """
-    parser.add_argument("--setup-type", help=
-                        """
-                        Type of setup:
-                            AIO-SX
-                            AIO-DX
-                            STANDARD
-                            STORAGE
-                        """,
-                        choices=['AIO-SX', 'AIO-DX', 'STANDARD', 'STORAGE'],
-                        type=str,
+    parser.add_argument("--setup-type",
+                        help=f"Expected value is one of {SetupType.get_members_values()}",
+                        type=SetupType,
                         required=True)
     parser.add_argument("--controllers", help=
                         """
@@ -174,7 +213,8 @@ def parse_config_location(parser: ArgumentParser):
     parser.add_argument("--ansible-controller-config", help=
                         """
                         Path to a local YAML file to be copied as localhost.yml
-                        to the home directory of the controller-0. NOTE: System password value is updated dynamically with user defined --password.
+                        to the home directory of the controller-0.
+                        NOTE: System password value is updated dynamically with user defined --password.
                         """,
                         type=str)
     parser.add_argument("--vbox-home-dir", help=
@@ -244,7 +284,7 @@ def parse_networking(parser: ArgumentParser):
 
     parser.add_argument("--vboxnet-name", help=
                         """
-                        Which host only network to use for setup.
+                        Which network to use for setup.
                         """,
                         type=str)
     parser.add_argument("--vboxnet-ip", help=
@@ -258,13 +298,10 @@ def parse_networking(parser: ArgumentParser):
                         Add a new NAT interface to hosts.
                         """,
                         action='store_true')
-    parser.add_argument("--vboxnet-type", help=
-                        """
-                        Type of vbox network, either hostonly on nat
-                        """,
-                        choices=['hostonly', 'nat'],
-                        type=str,
-                        default='hostonly')
+    parser.add_argument("--vboxnet-type",
+                        help=f"Expected value is one of {VboxNetworkType.get_members_values()}",
+                        type=VboxNetworkType,
+                        default=VboxNetworkType.HOST_ONLY)
     parser.add_argument("--nat-controller-floating-local-ssh-port", help=
                         """
                         When oam network is configured as 'nat' a port on