Greek-only letters

import re, subprocess

class GreekWords:
    re_greek= re.compile('(?ui)[γδθλξπσςφψΐΰωώ]')

    def all_words(self):
        with subprocess.Popen(
            'exec aspell -d el dump master | aspell -l el expand',
            shell=True, stdout=subprocess.PIPE, universal_newlines=True) as sub:
            yield from sub.stdout
        sub.wait()

    def most_greek(self):
        return max(self.all_words(), key=lambda i: len(self.re_greek.findall(i)))

    def most_unique_greek(self):
        return max(self.all_words(), key=lambda i: len(set(self.re_greek.findall(i))))