def METHOD_NAME(exec_name):
    """Try to find full path of exec_name
    Parameters
    ----------
    exec_name : str
        The executable name
    Returns
    -------
    path : str
        The full path of executable if found, otherwise returns None
    """
    base_list = ["", "/bin"] + os.environ.get("PATH", "").split(os.pathsep)
    for path in base_list:
        full_path = os.path.join(path, exec_name)
        if os.path.isfile(full_path) and os.access(full_path, os.X_OK):
            return full_path
    return None