code: def spline_factors(u):
      '''u is np.array'''
  
      X = np.array([(1.-u)**3 , 4-(6.*(u**2))+(3.*(u**3)) , 1.+(3.*u)+(3.*(u**2))-(3.*(u**3)) , u**3]) * (1./6)
      
      return f spline_factors(u):
      '''u is np.array'''
  
      X = np.array([(1.-u)**3 , 4-(6.*(u**2))+(3.*(u**3)) , 1.+(3.*u)+(3.*(u**2))-(3.*(u**3)) , u**3]) * (1./6)
      
      return X
docs: u is np.array