code: def uvw(self, context):
          
  
          # Shape (ntime, na, 3)
          (lt, ut), (la, ua), (l, u) = context.array_extents(context.name)
  
          # Create empty UVW coordinates
          data = np.empty(context.shape, context.dtype)
          data[:,:,0] = np.arange(la+1, ua+1)    # U = antenna index
          data[:,:,1] = 0                        # V = 0
          data[:,:,2] = 0                        # W = 0
  
          return data
docs: Supply UVW antenna coordinates to montblanc