Dataset: fix bug revealed by pandas 1.0
@@ -291,7 +291,7 @@ class ReactionDataset(Dataset):
# Multiply by coefficients and sum
df["return_result"] *= df["coefficient"]
- df = df.groupby(["name"])["return_result"].sum(skipna=False)
+ df = df.groupby(["name"])["return_result"].sum()
df[null_mask] = np.nan
return df
