Choose a C{pinentry} that can prompt you for a secret.

    @return: An argv list suitable for passing to L{ProcessEndpoint}

    @raises: L{RuntimeError} if no C{pinentry} is available.

    @see:
        U{https://www.gnupg.org/documentation/manuals/gnupg/Common-Problems.html}

def choosePinentry():
    """
    Choose a C{pinentry} that can prompt you for a secret.

    @return: An argv list suitable for passing to L{ProcessEndpoint}

    @raises: L{RuntimeError} if no C{pinentry} is available.

    @see:
        U{https://www.gnupg.org/documentation/manuals/gnupg/Common-Problems.html}
    """
    pinentries = []
    if 'PINENTRY' in os.environ:
        pinentries.append(Pinentry(os.environ['PINENTRY']))
    else:
        mgrd = yield call('launchctl', 'managername')
        if mgrd == 'Aqua':
            pinentries.extend([
                Pinentry(
                    '/usr/local/MacGPG2/libexec/pinentry-mac.app'
                    '/Contents/MacOS/pinentry-mac'),
                Pinentry('pinentry-mac'),
            ])
        if 'DISPLAY' in os.environ:
            pinentries.extend([
                Pinentry('pinentry-gnome3'),
                Pinentry('pinentry-x11')
            ])
        pinentries.extend([
            Pinentry('pinentry-curses'),
            Pinentry('pinentry'),
        ])

    for pinentry in pinentries:
        try:
            pinentry.argv()
        except (PinentryNotFound, OSError):
            continue
        else:
            return pinentry
    else:
        return GetPassAsker()