Gravity vector error when gravity is zero

[Ipuch]

Traceback (most recent call last):
  File "/home/puchaud/Projets_Python/Test_Pyomeca/energy_test/energy.py", line 68, in <module>
    biorbd_viz1 = bioviz.Viz(p, segments_center_of_mass_size=0.05)
  File "/home/puchaud/Projets_Python/Pyomeca_github/bioviz/bioviz/__init__.py", line 354, in __init__
    self.__set_gravity_vector()
  File "/home/puchaud/Projets_Python/Pyomeca_github/bioviz/bioviz/__init__.py", line 1206, in __set_gravity_vector
    self.vtk_model.new_gravity_vector(id_matrix, gravity, length, normalization_ratio=0.3, vector_color=(0, 0, 0))
  File "/home/puchaud/Projets_Python/Pyomeca_github/bioviz/bioviz/biorbd_vtk.py", line 1884, in new_gravity_vector
    length = length * normalization_ratio / length
ZeroDivisionError: float division by zero