Blender Path File Write

# -----------------------------------------
#  Here is a simple Python script for Blender (in Edit Mode) to write the
#  verts on the shortest path between two (pre-selected) points to a file.
#  (Change 'filename' and 'measurement' before running.  The script
#  appends new lines onto the file each time.)
# -----------------------------------------

import os, bpy, bmesh

# Ensure all folders of the path exist
path = "P:/"
os.makedirs(path, exist_ok=True)
filename = "measurement.txt"

measurement = "Label for measurement path"

oa = bpy.context.active_object
obj = bpy.context.object

bpy.ops.mesh.shortest_path_select() #add for request

me = obj.data
bm = bmesh.from_edit_mesh(me)

v1,v2 = [elem for elem in bm.select_history if isinstance(elem, bmesh.types.BMVert)]

list = [v1]
verts = len([v.index for v in bm.verts if v.select])

cont=0

while cont< verts:
    v=list[cont]
    edges = v.link_edges

    for e in edges:
        if e.select:
            vn = e.other_vert(v)
            if vn not in list:
                list.append(vn)

    cont+=1

ii = 0
outpath = ''
for v in list:
    if ii > 0:
        outpath = outpath + ','
    outpath = outpath + str(v.index)
    ii = ii + 1

with open(path + filename, "a+") as vertfile:
    vertfile.write(measurement+' ['+outpath+']\n')
bmesh.update_edit_mesh(me, True)