replace traceback

gistfile1.txt

ValueError                                Traceback (most recent call last)
<ipython-input-2-b8fda0fafe55> in <module>()
      2 ibm = web.DataReader("IBM", "yahoo", "1993/01/01").reset_index()
      3 next_date_dict = dict(zip(ibm["Date"], ibm["Date"].shift()))
----> 4 ibm_next_date = ibm["Date"].replace(next_date_dict)
      5 print (ibm_next_date == ibm["Date"]).all()

/local/install/pandas_test/lib/python2.7/site-packages/pandas/core/series.pyc in replace(self, to_replace, value, method, inplace, limit)
   2838 
   2839         if isinstance(to_replace, dict):
-> 2840             _rep_dict(result, to_replace)
   2841         elif isinstance(to_replace, (list, pa.Array)):
   2842 

/local/install/pandas_test/lib/python2.7/site-packages/pandas/core/series.pyc in _rep_dict(rs, to_rep)
   2829 
   2830                 for d, m in masks.iteritems():
-> 2831                     com._maybe_upcast_putmask(rs.values,m,d,change=change)
   2832             else:  # if no risk of clobbering then simple
   2833                 for d, sset in dd.iteritems():

/local/install/pandas_test/lib/python2.7/site-packages/pandas/core/common.pyc in _maybe_upcast_putmask(result, mask, other, dtype, change)
    851             np.putmask(result, mask, other)
    852         except:
--> 853             return changeit()
    854 
    855     return result, False

/local/install/pandas_test/lib/python2.7/site-packages/pandas/core/common.pyc in changeit()
    815             # we are forced to change the dtype of the result as the input isn't compatible
    816             r, fill_value = _maybe_upcast(result, fill_value=other, dtype=dtype, copy=True)
--> 817             np.putmask(r, mask, other)
    818 
    819             # we need to actually change the dtype here

ValueError: Invalid date (-1,-1,-1) when converting to NumPy datetime