BUG: add rail buttons checks in add_surfaces

rocketpy/rocket/rocket.py

@@ -966,14 +966,29 @@ def add_motor(self, motor, position): # pylint: disable=too-many-statements
  self.evaluate_com_to_cdm_function()
  self.evaluate_nozzle_gyration_tensor()
 
+ def __add_single_surface(self, surface, position):
+ """Adds a single aerodynamic surface to the rocket. Makes checks for
+ rail buttons case, and position type.
+ """
+ position = (
+ Vector([0, 0, position])
+ if not isinstance(position, (Vector, tuple, list))
+ else Vector(position)
+ )
+ if isinstance(surface, RailButtons):
+ self.rail_buttons.add(surface, position)
+ else:
+ self.aerodynamic_surfaces.add(surface, position)
+ self.__evaluate_single_surface_cp_to_cdm(surface, position)
+
  def add_surfaces(self, surfaces, positions):
  """Adds one or more aerodynamic surfaces to the rocket. The aerodynamic
  surface must be an instance of a class that inherits from the
  AeroSurface (e.g. NoseCone, TrapezoidalFins, etc.)
 
  Parameters
  ----------
- surfaces : list, AeroSurface, NoseCone, TrapezoidalFins, EllipticalFins, Tail
+ surfaces : list, AeroSurface, NoseCone, TrapezoidalFins, EllipticalFins, Tail, RailButtons
  Aerodynamic surface to be added to the rocket. Can be a list of
  AeroSurface if more than one surface is to be added.
  positions : int, float, list, tuple, Vector
@@ -996,22 +1011,11 @@ def add_surfaces(self, surfaces, positions):
  -------
  None
  """
- # TODO: separate this method into smaller methods: https://github.com/RocketPy-Team/RocketPy/pull/696#discussion_r1771978422
  try:
  for surface, position in zip(surfaces, positions):
- if not isinstance(position, (Vector, tuple, list)):
- position = Vector([0, 0, position])
- else:
- position = Vector(position)
- self.aerodynamic_surfaces.add(surface, position)
- self.__evaluate_single_surface_cp_to_cdm(surface, position)
+ self.__add_single_surface(surface, position)
  except TypeError:
- if not isinstance(positions, (Vector, tuple, list)):
- positions = Vector([0, 0, positions])
- else:
- positions = Vector(positions)
- self.aerodynamic_surfaces.add(surfaces, positions)
- self.__evaluate_single_surface_cp_to_cdm(surfaces, positions)
+ self.__add_single_surface(surfaces, positions)
 
  self.evaluate_center_of_pressure()
  self.evaluate_stability_margin()