Trouble making categorical variable --- TypeError: 'ClassRegistry' object is not callable

Not sure what's going on here.

In [44]: patsy.dmatrix("C(a)", {'a':['m', 'n', 'o']})
Out[44]:
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-44-24c8bf15ba3b> in <module>()
----> 1 dmatrix("C(a)", {'a':['m', 'n', 'o']})

/Users/mike/venv/sci/lib/python2.7/site-packages/patsy/highlevel.pyc in dmatrix(formula_like, data, eval_env, return_type)
    259     """
    260     (lhs, rhs) = _do_highlevel_design(formula_like, data, _get_env(eval_env),
--> 261                                       return_type)
    262     if lhs.shape[1] != 0:
    263         raise PatsyError("encountered outcome variables for a model "

/Users/mike/venv/sci/lib/python2.7/site-packages/patsy/highlevel.pyc in _do_highlevel_design(formula_like, data, eval_env, return_type)
    145     def data_iter_maker():
    146         return iter([data])
--> 147     builders = _try_incr_builders(formula_like, data_iter_maker, eval_env)
    148     if builders is not None:
    149         return build_design_matrices(builders, data,

/Users/mike/venv/sci/lib/python2.7/site-packages/patsy/highlevel.pyc in _try_incr_builders(formula_like, data_iter_maker, eval_env)
     59         return design_matrix_builders([formula_like.lhs_termlist,
     60                                        formula_like.rhs_termlist],
---> 61                                       data_iter_maker)
     62     else:
     63         return None

/Users/mike/venv/sci/lib/python2.7/site-packages/patsy/build.pyc in design_matrix_builders(termlists, data_iter_maker)
    691      cat_postprocessors) = _examine_factor_types(all_factors,
    692                                                  factor_states,
--> 693                                                  data_iter_maker)
    694     # Now we need the factor evaluators, which encapsulate the knowledge of
    695     # how to turn any given factor into a chunk of data:

/Users/mike/venv/sci/lib/python2.7/site-packages/patsy/build.pyc in _examine_factor_types(factors, factor_states, data_iter_maker)
    441             break
    442         for factor in list(examine_needed):
--> 443             value = factor.eval(factor_states[factor], data)
    444             if isinstance(value, Categorical):
    445                 postprocessor = CategoricalTransform(levels=value.levels)

/Users/mike/venv/sci/lib/python2.7/site-packages/patsy/eval.pyc in eval(self, memorize_state, data)
    429     #    http://nedbatchelder.com/blog/200711/rethrowing_exceptions_in_python.html
    430     def eval(self, memorize_state, data):
--> 431         return self._eval(memorize_state["eval_code"], memorize_state, data)
    432 
    433 def test_EvalFactor_basics():

/Users/mike/venv/sci/lib/python2.7/site-packages/patsy/eval.pyc in _eval(self, code, memorize_state, data)
    412     def _eval(self, code, memorize_state, data):
    413         inner_namespace = VarLookupDict([data, memorize_state["transforms"]])
--> 414         return self._eval_env.eval(code, inner_namespace=inner_namespace)
    415 
    416     def memorize_chunk(self, state, which_pass, data):

/Users/mike/venv/sci/lib/python2.7/site-packages/patsy/eval.pyc in eval(self, expr, source_name, inner_namespace)
    119         code = compile(expr, source_name, "eval", self.flags, False)
    120         return eval(code, {}, VarLookupDict([inner_namespace]
--> 121                                             + self._namespaces))
    122 
    123     @classmethod

<string> in <module>()

TypeError: 'ClassRegistry' object is not callable

Using virtualenv on a Mac. Python 2.7.3.
Pygments==1.5
cloud==2.6.9
distribute==0.6.31
ipython==0.13.1
matplotlib==1.2.0
nose==1.2.1
numpy==1.6.2
pandas==0.10.0
patsy==0.1.0
python-dateutil==2.1
pytz==2012h
pyzmq==2.2.0.1
readline==6.2.4.1
scipy==0.11.0
six==1.2.0
statsmodels==0.5.0
sympy==0.7.2
tornado==2.4.1
wsgiref==0.1.2

Reproduce the reported patsy.dmatrix("C(a)", ...) failure with the listed package versions. Start with the traceback paths in highlevel.py, build.py, and eval.py, then trace how C(a) is evaluated. Done means the categorical-variable example no longer raises this TypeError and has a regression test.