diff --git a/manimlib/mobject/vector_field.py b/manimlib/mobject/vector_field.py
index b349e7e5..ea809cb0 100644
--- a/manimlib/mobject/vector_field.py
+++ b/manimlib/mobject/vector_field.py
@@ -422,7 +422,7 @@ class StreamLines(VGroup):
             cs = self.coordinate_system
             for line in self.submobjects:
                 norms = [
-                    get_norm(self.func(*cs.p2c(point)))
+                    get_norm(self.func(cs.p2c(point)))
                     for point in line.get_points()
                 ]
                 rgbs = values_to_rgbs(norms)
@@ -467,7 +467,7 @@ class AnimatedStreamLines(VGroup):
 
         self.add_updater(lambda m, dt: m.update(dt))
 
-    def update(self, dt: float) -> None:
+    def update(self, dt: float = 0) -> None:
         stream_lines = self.stream_lines
         for line in stream_lines:
             line.time += dt