# Buggy code
def as_dtype(nbtype):
    """
    Return a numpy dtype instance corresponding to the given Numba type.
    NotImplementedError is if no correspondence is known.
    """
    if isinstance(nbtype, (types.Complex, types.Integer, types.Float)):
        return np.dtype(str(nbtype))
    if nbtype is types.bool_:
        return np.dtype("?")
    if isinstance(nbtype, (types.NPDatetime, types.NPTimedelta)):
        letter = _as_dtype_letters[type(nbtype)]
        if nbtype.unit:
            return np.dtype("%s[%s]" % (letter, nbtype.unit))
        else:
            return np.dtype(letter)
    if isinstance(nbtype, (types.CharSeq, types.UnicodeCharSeq)):
        letter = _as_dtype_letters[type(nbtype)]
        return np.dtype("%s%d" % (letter, nbtype.count))
    if isinstance(nbtype, types.Record):
        return nbtype.dtype
    raise NotImplementedError("%r cannot be represented as a Numpy dtype" % (nbtype,))


# Traceback (TypeError)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-15-3b23f7331ceb> in <module>()
----> 1 @jit(arg_types=[numba.double], ret_type=numba.double)
2 def is_REALLY_five(some_value):
3     for i in range(5):
4         if some_value == 5.0:
5             return 1.0

/Library/Frameworks/EPD64.framework/Versions/7.3/lib/python2.7/site-packages/numba/decorators.pyc in _jit(func)
77                   "garbage collected!" % (func,))
78         t = Translate(func, *args, **kws)
---> 79         t.translate()
80         __tr_map__[func] = t
81         return t.get_ctypes_func(llvm)

/Library/Frameworks/EPD64.framework/Versions/7.3/lib/python2.7/site-packages/numba/translate.pyc in translate(self)
926                     # Ensure we are playing with locals that might
927                     # actually precede the next block.
--> 928                     self.check_locals(i)
929
930                 self.crnt_block = i

/Library/Frameworks/EPD64.framework/Versions/7.3/lib/python2.7/site-packages/numba/translate.pyc in check_locals(self, i)
1135                 else:
1136                     assert next_locals is not None, "Internal compiler error!"
-> 1137             self._locals = next_locals[:]
1138
1139     def get_ctypes_func(self, llvm=True):

TypeError: 'NoneType' object has no attribute '__getitem__'

# Fixed code
def as_dtype(nbtype):
    """
    Return a numpy dtype instance corresponding to the given Numba type.
    NotImplementedError is if no correspondence is known.
    """
    if isinstance(nbtype, (types.Complex, types.Integer, types.Float)):
        return np.dtype(str(nbtype))
    if nbtype is types.bool_:
        return np.dtype("?")
    if isinstance(nbtype, (types.NPDatetime, types.NPTimedelta)):
        letter = _as_dtype_letters[type(nbtype)]
        if nbtype.unit:
            return np.dtype("%s[%s]" % (letter, nbtype.unit))
        else:
            return np.dtype(letter)
    if isinstance(nbtype, (types.CharSeq, types.UnicodeCharSeq)):
        letter = _as_dtype_letters[type(nbtype)]
        return np.dtype("%s%d" % (letter, nbtype.count))
    if isinstance(nbtype, types.Record):
        return nbtype.dtype
    if isinstance(nbtype, types.EnumMember):
        return as_dtype(nbtype.dtype)
    raise NotImplementedError("%r cannot be represented as a Numpy dtype" % (nbtype,))