code: def export_stl_ascii(mesh):
      
  
      # move all the data that's going into the STL file into one array
      blob = np.zeros((len(mesh.faces), 4, 3))
      blob[:, 0, :] = mesh.face_normals
      blob[:, 1:, :] = mesh.triangles
  
      # create a lengthy format string for the data section of the file
      format_string = 'facet normal {} {} {}\nouter loop\n'
      format_string += 'vertex {} {} {}\n' * 3
      format_string += 'endloop\nendfacet\n'
      format_string *= len(mesh.faces)
  
      # concatenate the header, data, and footer
      export = 'solid \n'
      export += format_string.format(*blob.reshape(-1))
      export += 'endsolid'
  
      return export
docs: Convert a Trimesh object into an ASCII STL file.
  
      Parameters
      ---------
      mesh : trimesh.Trimesh
  
      Returns
      ---------
      export : str
          Mesh represented as an ASCII STL file