code: def test_composition():
      p = poly.Polynomial([3, 2, 1], symbol="t")
      q = poly.Polynomial([5, 1, 0, -1], symbol="λ_1")
      r = p(q)
      assert r.symbol == "λ_1"
  
imports: import pytest
  import numpy.polynomial
  from numpy.core import array
  from numpy.testing import assert_equal, assert_raises, assert_
label_desc: Use image node_id 1 for calling a global function with example usage: test_composition() without return types