Add utils function for handling subprocess.

import subprocess

def and_(iter):

    """Do an and logic condition over the iterable element.

            return False

    return True

def subproc_call(args, stdin=None):

    """

    :param args: arguments for subprocess call

    :param stdin: stdin data as string

    """

    proc = subprocess.Popen(args, bufsize=4096, stdin=subprocess.PIPE,

                            stdout=subprocess.PIPE, stderr=subprocess.STDOUT)

    result, _ = proc.communicate(stdin)

    if proc.returncode != 0:

        raise subprocess.CalledProcessError(proc.returncode,

                                            'Error while executing command')

    return result