message: [bugfix] 'No numeric types to aggregate' in NVD3 chart
diff: @@ -225,15 +225,15 @@ class BaseViz(object):
  df[DTTM_ALIAS] += self.time_shift
  if self.enforce_numerical_metrics:
  - self.df_metrics_to_num(df, query_obj.get('metrics') or [])
  + self.df_metrics_to_num(df)
  df.replace([np.inf, -np.inf], np.nan)
  df = self.handle_nulls(df)
  return df
  - @staticmethod
  - def df_metrics_to_num(df, metrics):
  + def df_metrics_to_num(self, df):
  """Converting metrics to numeric when pandas.read_sql cannot"""
  + metrics = self.metric_labels
  for col, dtype in df.dtypes.items():
  if dtype.type == np.object_ and col in metrics:
  df[col] = pd.to_numeric(df[col], errors='coerce')
  