docs: def like_cosi(cosi,vsini_dist,veq_dist,vgrid=None):
      """likelihood of Data (vsini_dist, veq_dist) given cosi
      """
      sini = np.sqrt(1-cosi**2)
      def integrand(v):
          #return vsini_dist(v)*veq_dist(v/sini)
          return vsini_dist(v*sini)*veq_dist(v)
      if vgrid is None:
          return quad(integrand,0,np.inf)[0]
      else:
          return np.trapz(integrand(vgrid),vgrid)