retvals = []
for val, t in compat.izip(values, table.schema.types):
if pd.isnull(val):
retvals.append(None)
else:
retvals.append(val)
After Change
retvals = []
for val, t in compat.izip(values, table.schema.types):
isnull = pd.isnull(val)
if isinstance(isnull, bool) and isnull:
retvals.append(None)
else:
retvals.append(val)