FIX: Work around install weirdness

Author: effigies

nipype/info.py

@@ -167,12 +167,15 @@ def get_nipype_gitversion():
     # 'mesh': ['mayavi']  # Enable when it works
 }
 
-_list_union = lambda x: list(set(sum(x, [])))
+
+def _list_union(iterable):
+    return list(set(sum(iterable, [])))
+
 
 # Enable a handle to install all extra dependencies at once
 EXTRA_REQUIRES['all'] = _list_union(EXTRA_REQUIRES.values())
 # dev = doc + tests + specs
-EXTRA_REQUIRES['dev'] = _list_union(EXTRA_REQUIRES[key]
-                                    for key in ('doc', 'tests', 'specs'))
+EXTRA_REQUIRES['dev'] = _list_union(val for key, val in EXTRA_REQUIRES.items()
+                                    if key in ('doc', 'tests', 'specs'))
 
 STATUS = 'stable'