diff --git a/builders/builder.py b/builders/builder.py
index 4144b71..1d9b8e0 100644
--- a/builders/builder.py
+++ b/builders/builder.py
@@ -13,15 +13,15 @@ def flatten(l):
         Generator that flattens iterable infinitely. If an item is iterable, ``flatten`` descends on it.
         If it is callable, it descends on the call result (with no arguments), and it yields the item itself otherwise.
     """
-    for el in l:
-        if isinstance(el, collections.Iterable) and not isinstance(el, basestring):
+    if isinstance(l, collections.Iterable) and not isinstance(l, basestring):
+        for el in l:
             for sub in flatten(el):
                 yield sub
-        elif callable(el):
-            for sub in flatten(el()):
-                yield sub
-        else:
-            yield el
+    elif callable(l):
+        for sub in flatten(l()):
+            yield sub
+    else:
+        yield l
 
 
 class Builder:
diff --git a/builders/tests/test_builder.py b/builders/tests/test_builder.py
index a9430f8..264141f 100644
--- a/builders/tests/test_builder.py
+++ b/builders/tests/test_builder.py
@@ -175,6 +175,18 @@ def test_flatten():
     assert list(flatten(l)) == [1, 2, 3, 4, 5, 'ololo']
 
 
+def test_flatten_noniterable():
+    y = 100
+    assert list(flatten(y)) == [y]
+
+
+def test_flatten_function_returning_noniterable():
+    def y():
+        return 100
+
+    assert list(flatten(y)) == [100]
+
+
 def test_flatten_callable():
     def x():
         return [1, 2, 3]