code: def test_issue_6999():
      s = tanh(x).lseries(x, 1)
      assert next(s) == tanh(1)
      assert next(s) == x - (x - 1) * tanh(1) ** 2 - 1
      assert (
          next(s)
          == -((x - 1) ** 2) * tanh(1) + (x - 1) ** 2 * tanh(1) ** 3
      )
      assert (
          next(s)
          == -((x - 1) ** 3) * tanh(1) ** 4
          - (x - 1) ** 3 / 3
          + 4 * (x - 1) ** 3 * tanh(1) ** 2 / 3
      )
  
file_path: sympy/sympy/series/tests/test_lseries.py
imports: from sympy.core.numbers import E
  from sympy.core.singleton import S
  from sympy.functions.elementary.exponential import exp
  from sympy.functions.elementary.hyperbolic import tanh
  from sympy.functions.elementary.trigonometric import cos, sin
  from sympy.series.order import Order
  from sympy.abc import x, y
label_desc: Use image node_id 7 for calling a global function with example usage: test_issue_6999() without return types