remove redundant lambda

main.py

@@ -24,7 +24,7 @@ if __name__ == '__main__':
         x.append([e.lon, e.lat])
     x = np.array(x)
     db = DBSCAN(eps = 10/6400000, min_samples = 3,
-            metric = lambda x,y:metric.spherical_distance(x,y)).fit(x)
+            metric = metric.spherical_distance).fit(x)
     labels = db.labels_
     core_samples_mask = np.zeros_like(db.labels_, dtype = bool)
     core_samples_mask[db.core_sample_indices_] = True