docs: def hyperbola(axes, **kwargs):
      """
      Plots a hyperbola that opens along y axis
      """
      opens_up = kwargs.pop('opens_up', True)
      center = kwargs.pop('center', defaults['center'])
      th = N.linspace(0,2*N.pi,kwargs.pop('n', 500))
  
      vals = [N.tan(th),1/N.cos(th)]
      if not opens_up:
          vals = vals[::-1]
  
      x = axes[0]*vals[0]+center[0]
      y = axes[1]*vals[1]+center[1]
  
      extrema = [N.argmin(x),N.argmax(x)]
  
      def remove_asymptotes(arr):
          arr[extrema] = N.nan
          return arr
  
      xy = tuple(remove_asymptotes(i) for i in (x,y))
  
      return xy