docs: def atan2(y, x, context=None):
      """
      Return ``atan(y / x)`` with the appropriate choice of function branch.
  
      If ``x > 0``, then ``atan2(y, x)`` is mathematically equivalent to ``atan(y
      / x)``.  If ``x < 0`` and ``y > 0``, ``atan(y, x)`` is equivalent to ``π +
      atan(y, x)``.  If ``x < 0`` and ``y < 0``, the result is ``-π + atan(y,
      x)``.
  
      Geometrically, ``atan2(y, x)`` is the angle (measured counterclockwise, in
      radians) from the positive x-axis to the line segment joining (0, 0) to (x,
      y), in the usual representation of the x-y plane.
  
      Special values are handled as described in the ISO C99 and IEEE 754-2008
      standards for the atan2 function.  The following examples illustrate the
      rules for positive y; for negative y, apply the symmetry ``atan(-y, x) ==
      -atan(y, x)``.
  
          >>> finite = positive = 2.3
          >>> negative = -2.3
          >>> inf = BigFloat('inf')
  
          >>> print(atan2(+0.0, -0.0))     # pi
          3.1415926535897931
          >>> print(atan2(+0.0, +0.0))     # 0
          0
          >>> print(atan2(+0.0, negative)) # pi
          3.1415926535897931
          >>> print(atan2(+0.0, positive)) # 0
          0
          >>> print(atan2(positive, 0.0))  # pi / 2
          1.5707963267948966
          >>> print(atan2(inf, -inf))      # 3*pi / 4
          2.3561944901923448
          >>> print(atan2(inf, inf))       # pi / 4
          0.78539816339744828
          >>> print(atan2(inf, finite))    # pi / 2
          1.5707963267948966
          >>> print(atan2(positive, -inf)) # pi
          3.1415926535897931
          >>> print(atan2(positive, +inf)) # 0
          0
  
      """
      return _apply_function_in_current_context(
          BigFloat,
          mpfr.mpfr_atan2,
          (
              BigFloat._implicit_convert(y),
              BigFloat._implicit_convert(x),
          ),
          context,
      )