Remove now unused Version.to_string()

- `v.to_string(short=False)` was replaced by `str(v)`
- `v.to_string(short=True)` was replaced by `v.short_str()`

picard/version.py

@@ -77,12 +77,6 @@ def from_string(cls, version_str):
     def valid_identifiers(cls):
         return set(cls._identifiers.keys())
 
-    def to_string(self, short=False):
-        if short:
-            return self.short_str()
-        else:
-            return str(self)
-
     def short_str(self):
         if self.identifier in {'alpha', 'beta'}:
             version = self._replace(identifier=self.identifier[0])

test/test_versions.py

@@ -52,7 +52,6 @@ def test_version_conversion(self):
         )
         for v, s in versions:
             self.assertEqual(str(v), s)
-            self.assertEqual(v.to_string(), s)
             self.assertEqual(v, Version.from_string(s))
 
     def test_version_conversion_short(self):