Generates a random phrase which consists of few words separated by spaces.
        The first word is capitalized, others are not.

        :param min_size: (optional) minimum string length.

        :param max_size: maximum string length.

        :return: a random phrase.

def phrase(min_size, max_size = None):
        """
        Generates a random phrase which consists of few words separated by spaces.
        The first word is capitalized, others are not.

        :param min_size: (optional) minimum string length.

        :param max_size: maximum string length.

        :return: a random phrase.
        """
        max_size = max_size if max_size != None else min_size
        size = RandomInteger.next_integer(min_size, max_size)
        if size <= 0:
            return ""
        
        result = ""
        result += random.choice(_all_words)
        while len(result) < size:
            result += " " + random.choice(_all_words).lower()

        return result