How to use the rstr.xeger function in rstr

def run_operation():
    for vmname, image in images.iteritems():
        print "\n{} - {}: {} \n".format(operation, vmname, image)
        uid = rstr.xeger(r'[0-9a-fA-F]{8}')
        vmname = vmname.lower() + '-' + uid
        dnsname = vmname
        if operation == 'Create VM and Add Extension':
            create_vm(rGroup, vmname, image, username, password, location, dnsname, size, nsg)
            remove_extension(extension, vmname, rGroup)
            copy_to_vm(dnsname, username, password, location)
            run_command(rGroup, vmname, 'RunShellScript', 'python /tmp/omsStatusCheck.py -preinstall')
            add_extension(extension, publisher, vmname, rGroup, private_settings, public_settings)
            run_command(rGroup, vmname, 'RunShellScript', 'python /tmp/omsStatusCheck.py -postinstall')
            copy_from_vm(dnsname, username, password, location)
        elif operation == 'Create VM':
            create_vm(rGroup, vmname, image, username, password, location, dnsname, size, nsg)
        elif operation == 'Add Extension':
            add_extension(extension, publisher, vmname, rGroup, private_settings, public_settings)
            run_command(rGroup, vmname, 'RunShellScript', 'python /tmp/omsStatusCheck.py -status')
            copy_from_vm(dnsname, username, password, location)

def _get_string(self, low=None, high=None, pattern=None):
        """Return string from `pattern` or a universal pattern
        [0-9a-zA-Z].
        """
        low, high = self._render_range(low, high)
        if pattern is None or is_match_all(pattern):
            pattern = r'[0-9a-zA-Z]'
        return rstr.xeger(pattern).rstrip("\\\"")

def create_vm_and_install_old_extension():
    """Create vm and install a specific version of the extension, returning HTML results."""

    message = ""
    update_option = '--version {0} --no-auto-upgrade'.format(old_version)
    install_times.clear()
    for distname, image in images.iteritems():
        uid = rstr.xeger(r'[0-9a-f]{8}')
        vmname = get_vm_name(distname, uid)
        vmnames.append(vmname)
        dnsname = vmname
        vm_log_file = distname.lower() + "result.log"
        vm_html_file = distname.lower() + "result.html"
        log_open = open(vm_log_file, 'a+')
        html_open = open(vm_html_file, 'a+')
        print("\nCreate VM and Install Extension {0} v-{1} - {2}: {3} \n".format(extension, old_version, vmname, image))
        create_vm(resource_group, vmname, image, username, ssh_public, location, dnsname, size, nsg_uri)
        copy_to_vm(dnsname, username, ssh_private, location)
        delete_extension(extension, vmname, resource_group)
        run_az_command(resource_group, vmname, 'RunShellScript', 'python -u /tmp/oms_extension_run_script.py -preinstall')
        add_extension(extension, publisher, vmname, resource_group, private_settings, public_settings, update_option)
        run_az_command(resource_group, vmname, 'RunShellScript', 'python -u /home/scratch/oms_extension_run_script.py -postinstall')
        install_times.update({vmname: datetime.now()})
        run_az_command(resource_group, vmname, 'RunShellScript', 'python -u /home/scratch/oms_extension_run_script.py -injectlogs')

Creates stub/plus status url based on context

        :param ctx: {} of current parsing context
        :param server_preferred: bool - use server_name instead of listen
        :return: [] of urls
        """
        location = ctx.get('location', '/')

        # remove all modifiers
        location_parts = location.split(' ')
        final_location_part = location_parts[-1]

        # generate a random sting that will fit regex location
        if location.startswith('~'):
            try:
                exact_location = rstr.xeger(final_location_part)

                # check that regex location has / and add it
                if not exact_location.startswith('/'):
                    exact_location = '/%s' % exact_location
            except:
                context.log.debug('bad regex location: %s' % final_location_part)
                exact_location = None
        else:
            exact_location = final_location_part

            # if an exact location doesn't have / that's not a working location, we should not use it
            if not exact_location.startswith('/'):
                context.log.debug('bad exact location: %s' % final_location_part)
                exact_location = None

        if exact_location:

def gen_regex(regex):
    return rstr.xeger(regex)

example = []
        samples = random.randint(3, 5)
        if 'type' not in rule['schema']:
          specification = {'type': 'string'}

          if 'regex' in rule['schema']:
            if rule['schema']['regex'] == '\w+\.\w+\_\w+':
              # special on for permissions
              p = Permission.objects.all()
              for _ in range(samples):
                c = random.randint(0, p.count())
                example.append("{1}.{0}".format(p[c].codename, p[c].content_type.app_label))
            else:
              specification['pattern'] = rule['schema']['regex']
              for _ in range(samples):
                example.append(rstr.xeger(rule['schema']['regex']))

        elif rule['schema']['type'] in ['email', 'date', 'uuid']:
          specification = {'type': 'string', 'format': rule['schema']['type']}

          if rule['schema']['type'] == 'email':
            for _ in range(samples):
              example.append(fake.email())

          if rule['schema']['type'] == 'uuid':
            for _ in range(samples):
              example.append(str(uuid.uuid4()))

        else:
          specification = {'type': rule['schema']['type']}

        converted = {'type': 'array', 'items': specification}

def generate_value(self, avoided_value):
        if not self.REGEX:
            return ["Example String Value"]

        return [rstr.xeger(self.REGEX)]

def random_value(self, override=None):
        if self.validate_value(override):
            return override
        return rstr.xeger(self.pattern)