Merge branch 'issue-035-037' of git.ecdf.ed.ac.uk:swain-lab/aliby/aliby into issue-035-037

src/postprocessor/core/reshapers/picker.py

@@ -102,8 +102,8 @@ class picker(LineageProcess):
             self.daughters = np.array([])
         else:
             self.mothers, self.daughters = (
-                self.cells.mothers_daughters[:, 1],
-                self.cells.mothers_daughters[:, 2],
+                tuple(self.cells.mothers_daughters[:, 1]),
+                tuple(self.cells.mothers_daughters[:, 2]),
             )
         for alg, op, *params in self.sequence:
             if indices: