Check configuration file type is yaml
    Return a boolean indicating wheather the file is yaml format or not

def is_yaml_file(filename, show_warnings = False):
    """Check configuration file type is yaml
    Return a boolean indicating wheather the file is yaml format or not
    """
    if is_json_file(filename):
        return(False)
    try:
        config_dict = load_config(filename, file_type = "yaml")
        if(type(config_dict) == str):
            is_yaml = False
        else:
            is_yaml = True
    except:
        is_yaml = False
    return(is_yaml)