def __evalthis(exp, title, value):
    """ Private function that evaluates given expression and returns true or false
        if expression is blank returns true
    """
    if exp == '':
        return True
    for a in range(0, len(title)):
        if value[a].isdigit():
            r = value[a]
        else:
            r = '"' + value[a] + '"'
        exp = exp.replace(str(title[a]), r)
    return eval(exp)
