code: def test_dim():
      dimsys = DimensionSystem(
          (length, mass, time),
          (velocity, action),
          {
              velocity: {length: 1, time: -1},
              action: {mass: 1, length: 2, time: -1},
          },
      )
      assert dimsys.dim == 3
  
file_path: sympy/sympy/physics/units/tests/test_dimensionsystem.py
imports: from sympy.core.symbol import symbols
  from sympy.matrices.dense import Matrix, eye
  from sympy.physics.units.definitions.dimension_definitions import action, current, length, mass, time, velocity
  from sympy.physics.units.dimensions import DimensionSystem
label_desc: Use image node_id 8 for calling a global function with example usage: test_dim() without return types