code: def circle_se(radius):
      """
      circle = circle_se(radius)
  
      Build a circular structuring element of a given radius
  
      Parameters
      ----------
      radius : int
          Radius of circle
  
      Returns
      -------
      circle : boolean ndarray
      """
      if not (radius > 0):
          raise ValueError(
              "mahotas.morph.circle: radius must be positive"
          )
      X = np.arange(-radius, +radius + 1)
      X, Y = np.meshgrid(X, X)
      return (X**2 + Y**2) < radius**2
  
imports: from __future__ import division
  import numpy
  from .internal import _get_output, _verify_is_integer_type, _check_2
  from .None import _morph
label_desc: Use image node_id 21 for calling a global function with example usage: circle_se(radius) and returns: unknown