Fix a RuntimeError on Python 3.7

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 - Fixed `self:update` command on Windows.
 - Fixed `self:update` not picking up new versions.
+- Fixed a `RuntimeError` on Python 3.7.
 
 
 ## [0.10.2] - 2018-05-31

poetry/toml/prettify/elements/abstracttable.py

@@ -21,7 +21,10 @@ class AbstractTable(ContainerElement, traversal.TraversalMixin, dict):
         """
         non_metadata = self._enumerate_non_metadata_sub_elements()
         while True:
+            try:
                 yield next(non_metadata), next(non_metadata)
+            except StopIteration:
+                return
 
     def items(self):
         for (key_i, key), (value_i, value) in self._enumerate_items():