code: def test_Limits_simple_4a():
      a = Symbol("a")
      assert limit((sqrt(x) - sqrt(a)) / (x - a), x, a) == 1 / (
          2 * sqrt(a)
      )  # Primer 5
      assert limit((sqrt(x) - 1) / (root3(x) - 1), x, 1) == Rational(
          3, 2
      )  # 205
      assert limit((sqrt(1 + x) - sqrt(1 - x)) / x, x, 0) == 1  # 207
      assert limit(sqrt(x**2 - 5 * x + 6) - x, x, oo) == Rational(
          -5, 2
      )
  
imports: from sympy.core.numbers import Rational, oo, pi
  from sympy.core.singleton import S
  from sympy.core.symbol import Symbol
  from sympy.functions.elementary.exponential import exp, log
  from sympy.functions.elementary.miscellaneous import root, sqrt
  from sympy.functions.elementary.trigonometric import asin, cos, sin, tan
  from sympy.polys.rationaltools import together
  from sympy.series.limits import limit
label_desc: Use image node_id 9 for calling a global function with example usage: test_Limits_simple_4a() without return types