import hashlib


def list_hash(str_list):
    """
    Return a hash value for a given list of string.

    :param str_list: a list of strings (e.g. x_test)
    :type str_list: list (of str)
    :returns: an MD5 hash value
    :rtype: str
    """
    m = hashlib.md5()
    for doc in str_list:
        try:
            m.update(doc)
        except (TypeError, UnicodeEncodeError):
            m.update(doc.encode('ascii', 'ignore'))
    return m.hexdigest()