text: from sympy.core.backend import symbols
  from sympy.physics.mechanics import dynamicsymbols
  from sympy.physics.mechanics import ReferenceFrame, Point, Particle
  from sympy.physics.mechanics import LagrangesMethod, Lagrangian
  
  ### This test asserts that a system with more than one external forces
  ### is acurately formed with Lagrange method (see issue #8626)
  
  def test_lagrange_2forces():
      ### Equations for two damped springs in serie with two forces
  
      ### generalized coordinates
      q1, q2 = dynamicsymbols('q1, q2')
      ### generalized speeds
      q1d, q2d = dynamicsymbols('q1, q2', 1)
  
      ### Mass, spring strength, friction coefficient
      m, k, nu = symbols('m, k, nu')
  
      N = ReferenceFrame('N')
      O = Point('O')
  
      ### Two points
      P1 = O.locatenew('P1', q1 * N.x)
      P1.set_vel(N, q1d * N.x)
      P2 = O.locatenew('P1', q2 * N.x)
      P2.set_vel(N, q2d * N.x)
  
      pP1 = Particle('pP1', P1, m)
      pP1.potential_energy = k * q1**2 / 2
  
      pP2 = Particle('pP2', P2, m)
      pP2.potential_energy = k * (q1 - q2)**2 / 2
  
      #### Friction forces
      forcelist = [(P1, - nu * q1d * N.x),
                   (P2, - nu * q2d * N.x)]
      lag = Lagrangian(N, pP1, pP2)
  
      l_method = LagrangesMethod(lag, (q1, q2), forcelist=forcelist, frame=N)
      l_method.form_lagranges_equations()
  
      eq1 = l_method.eom[0]
      assert eq1.diff(q1d) == nu
      eq2 = l_method.eom[1]
      assert eq2.diff(q2d) == nu
  