def substitute_all_by_empty(qry_string, qry_subs):
    """Substitute all occurrences of specific string sequences by an empty sequence.
    
    Args:
        qry_string: A string containing sequences to be replaced.
        qry_subs: A list of strings containing sequences to be replaced.
    
    Returns:
        The qry_string where all sequences defined in qry_subs are deleted.
    """
    tmp_str = qry_string
    for sub in qry_subs:
        tmp_str = tmp_str.replace(sub, '')
    return tmp_str