text: from .sknw import mark, parse_struc, build_graph, draw_graph, build_sknw
  
  __version__ = '0.1'
  
  __all__ = ['mark', 'parse_struc', 'build_graph', 'draw_graph', 'build_sknw']
  
  
  def test():
      from skimage.morphology import skeletonize
      import numpy as np
      from skimage import data
      import matplotlib.pyplot as plt
  
      img = data.horse()
      ske = skeletonize(~img).astype(np.uint16)
      graph = build_sknw(ske)
      plt.imshow(img, cmap='gray')
      for (s,e) in graph.edges():
          ps = graph[s][e]['pts']
          plt.plot(ps[:,1], ps[:,0], 'green')
  
      nodes = graph.nodes()
      ps = np.array([nodes[i]['o'] for i in nodes])
      plt.plot(ps[:,1], ps[:,0], 'r.')
      plt.title('Build Graph')
      plt.show()
  