Simplify things

bilby/core/result.py

@@ -168,10 +168,7 @@ def rejection_sample(posterior, weights):
 
     """
     keep = weights > np.random.uniform(0, max(weights), weights.shape)
-    if isinstance(posterior, np.ndarray):
-        return posterior[keep]
-    elif isinstance(posterior, pd.DataFrame):
-        return posterior.iloc[keep]
+    return posterior[keep]
 
 
 def reweight(result, label=None, new_likelihood=None, new_prior=None,