How to use Python create navigation mesh for PandAI ?

Scripting Issues
#1

This is my code:

def createNavMesh(self, mesh, gridWidth):
	"""将生成的网格保存为.csv文件"""
	file_object = open(sys.path[0]+"/navmesh.csv", "w")
	try:
		file_object.write("Grid Size,")
		file_object.write(str(gridWidth))
		file_object.write("\nNULL, NodeType, GridX, GridY, Length, Width, Height, PosX, PosY, PosZ")
		for x in range(0,gridWidth):
			for y in range(0,gridWidth):
				file_object.write("\n1,")
				file_object.write(str(mesh[y][x]))
				file_object.write(",")
				file_object.write(str(x))
				file_object.write(",")
				file_object.write(str(y))
				file_object.write(",1,1,0,")
				file_object.write(str(x))
				file_object.write(",")
				file_object.write(str(y))
				file_object.write(",0")
	finally:
		file_object.close()

But this navmesh.csv can’t work.

#2

I want to know the mavigation mesh format for pandai.