Support tuples for random_crystal

Bugfix for _check_consistency for tuples, otherwise causes the following error: TypeError: int() argument must be a string, a bytes-like object or a real number, not 'tuple'

pyxtal/crystal.py

@@ -404,6 +404,9 @@ def _check_consistency(self, site, numIon):
             if isinstance(s, dict):
                 for key in s:
                     num += int(key[:-1])
+            elif isinstance(s, tuple):
+                (letter, x, y, z) = s
+                num += int(letter[:-1])
             else:
                 num += int(s[:-1])
         if numIon == num: