message: Fix edge case around NaN values
diff: @@ -223,7 +223,7 @@ class BaseViz(object):
  """Converting metrics to numeric when pandas.read_sql cannot"""
  for col, dtype in df.dtypes.items():
  if dtype.type == np.object_ and col in metrics:
  - df[col] = pd.to_numeric(df[col])
  + df[col] = pd.to_numeric(df[col], errors='coerce')
  def query_obj(self):
  """Building a query object"""
  