def get_species_list_from_potcar(filename="POTCAR"):
    """
    Generates the species list from a POTCAR type file

    Args:
        filename (str): Input filename

    Returns:
        list: A list of species symbols

    """
    trigger = "VRHFIN ="
    species_list = list()
    with open(filename) as potcar_file:
        lines = potcar_file.readlines()
        for line in lines:
            line = line.strip()
            if trigger in line:
                str_1 = line.split(trigger)
                str_2 = str_1[-1].split(":")
                species_list.append(str_2[0].replace(" ", ""))
    return species_list