I am trying to generate tree with fasta file input and Alignment with MuscleCommandline

import sys,os, subprocess

from Bio import AlignIO

from Bio.Align.Applications import MuscleCommandline

cline = MuscleCommandline(input="c:\Python26\opuntia.fasta")

child= subprocess.Popen(str(cline),

                     stdout = subprocess.PIPE,

                     stderr=subprocess.PIPE,

                    shell=(sys.platform!="win32"))

align=AlignIO.read(child.stdout,"fasta")

outfile=open('c:\Python26\opuntia.phy','w')

AlignIO.write([align],outfile,'phylip')

outfile.close()

I always encounter with these problems

Traceback (most recent call last):

File "", line 244, in run_nodebug

File "C:\Python26\muscleIO.py", line 11, in

align=AlignIO.read(child.stdout,"fasta")

File "C:\Python26\Lib\site-packages\Bio\AlignIO_init_.py", line 423, in read

raise ValueError("No records found in handle")

ValueError: No records found in handle