code: def test_fit():
      x, y = (range(10),) * 2
      p = poly.Polynomial.fit(x, y, deg=1, symbol="z")
      assert_equal(p.symbol, "z")
  
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 2 for calling a global function with example usage: test_fit() without return types