Fix Traitlets API 42. Help is in constructor, not tag.

IPython/core/historyapp.py

@@ -34,11 +34,13 b' This is an handy alias to `ipython history trim --keep=0`'
 class HistoryTrim(BaseIPythonApplication):
     description = trim_hist_help
     
-    backup = Bool(False).tag(config=True,
-        help="Keep the old history file as history.sqlite.<N>")
+    backup = Bool(False,
+        help="Keep the old history file as history.sqlite.<N>"
+        ).tag(config=True)
     
-    keep = Int(1000).tag(config=True,
-        help="Number of recent lines to keep in the database.")
+    keep = Int(1000,
+        help="Number of recent lines to keep in the database."
+        ).tag(config=True)
     
     flags = Dict(dict(
         backup = ({'HistoryTrim' : {'backup' : True}},
@@ -118,11 +120,12 b' class HistoryTrim(BaseIPythonApplication):'
 
 class HistoryClear(HistoryTrim):
     description = clear_hist_help
-    keep = Int(0).tag(config=False,
+    keep = Int(0,
         help="Number of recent lines to keep in the database.")
     
-    force = Bool(False).tag(config=True,
-        help="Don't prompt user for confirmation")
+    force = Bool(False,
+        help="Don't prompt user for confirmation"
+        ).tag(config=True)
     
     flags = Dict(dict(
         force = ({'HistoryClear' : {'force' : True}},

IPython/core/prompts.py

@@ -273,17 +273,19 b' class PromptManager(Configurable):'
         """)
     def _lazy_evaluate_fields_default(self): return lazily_evaluate.copy()
 
-    in_template = Unicode('In [\\#]: ').tag(config=True,
-        help="Input prompt.  '\\#' will be transformed to the prompt number")
-    in2_template = Unicode('   .\\D.: ').tag(config=True,
-        help="Continuation prompt.")
-    out_template = Unicode('Out[\\#]: ').tag(config=True,
-        help="Output prompt. '\\#' will be transformed to the prompt number")
-
-    justify = Bool(True).tag(config=True, help="""
+    in_template = Unicode('In [\\#]: ',
+        help="Input prompt.  '\\#' will be transformed to the prompt number"
+        ).tag(config=True)
+    in2_template = Unicode('   .\\D.: ',
+        help="Continuation prompt.").tag(config=True)
+    out_template = Unicode('Out[\\#]: ',
+        help="Output prompt. '\\#' will be transformed to the prompt number"
+        ).tag(config=True)
+
+    justify = Bool(True, help="""
         If True (default), each prompt will be right-aligned with the
         preceding one.
-        """)
+        """).tag(config=True)
 
     # We actually store the expanded templates here:
     templates = Dict()