Align Object Across a Spline

I have an arrow object and i want to align it based in different splines in the scene. I have splines going left, right and straight. I want the arrow to start at a point on spline and follow its direction. I am not sure how I can align the arrow based on the spline. I am working in a python script and want to make sure I can apply the same logic across multiple splines in different directions.

can you try to draw a pic showing us what you mean here

and by spline what do you mean ?
is it a Bezier curve or a real spline curve ?

and what is this arrow is it an object In blender
show us pic

thanks

I am attaching the picture below. Yes by spline I mean a Bezier curve. Arrow is an object I created in blender. I have attached an image of a similar scenario with a plane object in blender. It can be assumed that I rotated the plane but since I am generating multiple splines I am not able to align it accurately along the curve. I would like it to look a bit tilted towards the left in this scenario.

[ATTACH=CONFIG]291959[/ATTACH]

I am attaching the picture below. Yes by spline I mean a Bezier curve. Arrow is an object I created in blender. I have attached an image of a similar scenario with a plane object in blender. It can be assumed that I rotated the plane but since I am generating multiple splines I am not able to align it accurately along the curve. I would like it to look a bit tilted towards the left in this scenario.

[ATTACH=CONFIG]291959[/ATTACH]