def get_column_name(dataframe, valid_column_names):
    """
    Checks which valid column name is in dataframe and returns it if it exists.
    If more than one valid column name exists the first one is considered only.
    """
    for valid_column_name in valid_column_names:
        if valid_column_name in dataframe.columns:
            return valid_column_name
    return None