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+## Array#traverse
+
+    require 'facets/array/traverse'
+    
+Construct a new array created by traversing the array and its sub-arrays,
+executing the given block on the elements.
+
+    h = ['A', 'B', ['X', 'Y']]
+    g = h.traverse{ |e| e.downcase }
+    g.assert = ['a','b',['x', 'y']]
+    
+## Array#traverse!
+
+Like #traverse, but will change the array in place.
+
+    h = ['A', 'B', ['X', 'Y']]
+    h.traverse!{ |e| e.downcase }
+    h.assert = ['a','b',['x', 'y']]
+
+