How to use the amplify.agent.common.util.subp.call function in amplify

def nginx_installed():
    try:
        subp.call('/usr/sbin/nginx -V')
        return True
    except:
        return False

def teardown_method(self, method):
        # use check=False because sometimes this returns code 123 on test-plus for some reason
        subp.call('pgrep nginx | sudo xargs kill -9', check=False)
        subp.call('rm -f %s' % self.conf_path, check=False)
        super(RealNginxTempFileTestCase, self).teardown_method(method)

def reload_nginx(self):
        subp.call('service nginx reload', check=False)
        time.sleep(0.5)

def proc_cpuinfo(self):
        """ cat /proc/cpuinfo """
        proc_cpuinfo_out, _ = subp.call('cat /proc/cpuinfo')
        for line in proc_cpuinfo_out:
            kv = re.match(self.proc_cpuinfo_re, line)
            if kv:
                key, value = kv.group(1), kv.group(2)
                if key.startswith('model name'):
                    self.meta['processor']['model'] = value
                elif key.startswith('cpu cores'):
                    self.meta['processor']['cores'] = value

def version_parser(bin_path):
    """
    Runs version command and parses verson of mysqld

    :param bin_path: str bin path
    :return: str version
    """
    try:
        raw_stdout, _ = subp.call(VERSION_CMD % bin_path)

        # also trying to get the first line of output
        # here's the line that we are interested in::
        # mysqld  Ver 5.5.55-0ubuntu0.14.04.1 for debian-linux-gnu on x86_64 ((Ubuntu))
        raw_line = raw_stdout[0]
    except Exception as e:
        exc_name = e.__class__.__name__
        # this is being logged as debug only since we will rely on bin_path
        # collection error to tip off support as to what is going wrong with
        # version detection
        context.log.debug(
            'failed to get version info from "%s" due to %s' %
            (bin_path, exc_name)
        )
        context.log.debug('additional info:', exc_info=True)
    else:

def linux_name():
    try:
        out, err = subp.call('cat /etc/*-release')
    except AmplifySubprocessError:
        try:
            out, err = subp.call('uname -s')
            return out[0].lower()
        except AmplifySubprocessError:
            return 'unix'

    for line in out:
        if line.startswith('ID='):
            return line[3:].strip('"').lower()

    full_output = '\n'.join(out).lower()
    if 'oracle linux' in full_output:
        return 'rhel'
    elif 'red hat' in full_output:
        return 'rhel'
    elif 'centos' in full_output:
        return 'centos'
    else:

def linux_name():
    try:
        out, err = subp.call('cat /etc/*-release')
    except AmplifySubprocessError:
        try:
            out, err = subp.call('uname -s')
            return out[0].lower()
        except AmplifySubprocessError:
            return 'unix'

    for line in out:
        if line.startswith('ID='):
            return line[3:].strip('"').lower()

    full_output = '\n'.join(out).lower()
    if 'oracle linux' in full_output:
        return 'rhel'
    elif 'red hat' in full_output:
        return 'rhel'

def lscpu(self):
        """ lscpu """
        lscpu_out, _ = subp.call('lscpu')
        for line in lscpu_out:
            kv = re.match(self.lscpu_re, line)
            if kv:
                key, value = kv.group(1), kv.group(2)
                if key == 'Architecture':
                    self.meta['processor']['architecture'] = value
                elif key == 'CPU MHz':
                    self.meta['processor']['mhz'] = value
                elif key == 'Hypervisor vendor':
                    self.meta['processor']['hypervisor'] = value
                elif key == 'Virtualization type':
                    self.meta['processor']['virtualization'] = value
                elif key == 'CPU(s)':
                    self.meta['processor']['cpus'] = value
                elif 'cache' in key:
                    key = key.replace(' cache', '')

def proc_cpuinfo(meta):
        """ cat /proc/cpuinfo """
        proc_cpuinfo_out, _ = subp.call('cat /proc/cpuinfo')
        for line in proc_cpuinfo_out:
            kv = re.match('([\w|\s]+):\s*(.+)', line)
            if kv:
                key, value = kv.group(1), kv.group(2)
                if key.startswith('model name'):
                    meta['processor']['model'] = value
                elif key.startswith('cpu cores'):
                    meta['processor']['cores'] = value