---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-13-e4cbeb3de608> in <module>()
----> 1 grades.astype('time')
~\AppData\Local\Continuum\anaconda2\envs\python3\lib\site-packages\pandas\util\_decorators.py in wrapper(*args, **kwargs)
176 else:
177 kwargs[new_arg_name] = new_arg_value
--> 178 return func(*args, **kwargs)
179 return wrapper
180 return _deprecate_kwarg
~\AppData\Local\Continuum\anaconda2\envs\python3\lib\site-packages\pandas\core\generic.py in astype(self, dtype, copy, errors, **kwargs)
4999 # else, only a single dtype is given
5000 new_data = self._data.astype(dtype=dtype, copy=copy, errors=errors,
-> 5001 **kwargs)
5002 return self._constructor(new_data).__finalize__(self)
5003
~\AppData\Local\Continuum\anaconda2\envs\python3\lib\site-packages\pandas\core\internals.py in astype(self, dtype, **kwargs)
3712
3713 def astype(self, dtype, **kwargs):
-> 3714 return self.apply('astype', dtype=dtype, **kwargs)
3715
3716 def convert(self, **kwargs):
~\AppData\Local\Continuum\anaconda2\envs\python3\lib\site-packages\pandas\core\internals.py in apply(self, f, axes, filter, do_integrity_check, consolidate, **kwargs)
3579
3580 kwargs['mgr'] = self
-> 3581 applied = getattr(b, f)(**kwargs)
3582 result_blocks = _extend_blocks(applied, result_blocks)
3583
~\AppData\Local\Continuum\anaconda2\envs\python3\lib\site-packages\pandas\core\internals.py in astype(self, dtype, copy, errors, values, **kwargs)
573 def astype(self, dtype, copy=False, errors='raise', values=None, **kwargs):
574 return self._astype(dtype, copy=copy, errors=errors, values=values,
--> 575 **kwargs)
576
577 def _astype(self, dtype, copy=False, errors='raise', values=None,
~\AppData\Local\Continuum\anaconda2\envs\python3\lib\site-packages\pandas\core\internals.py in _astype(self, dtype, copy, errors, values, klass, mgr, **kwargs)
634
635 # astype processing
--> 636 dtype = np.dtype(dtype)
637 if self.dtype == dtype:
638 if copy:
TypeError: data type "time" not understood