Add support for Rangy input in parse_range function and implement cor…

…responding test

rangy/parse.py

@@ -144,6 +144,10 @@ def parse_range(range_input):
     Raises:
         ParseRangeError: If the input is invalid or cannot be parsed.
     """
+    from rangy import Rangy
+    # short circuit if it's already a rangy
+    if isinstance(range_input, Rangy):
+        return range_input.values
 
     start, end = _normalize_to_sequence(range_input)
 

tests/parser/test_from_rangy.py

@@ -0,0 +1,7 @@
+import pytest
+
+from rangy import parse_range, Rangy
+
+def test_from_rangy():
+    res = parse_range(Rangy((1, 3)))
+    assert res == (1, 3)