Python CGI script, i am not able to pass '+' plus operator as a parameter
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I am trying to pass a parameter to a python cgi script, this parameter contains the plus operator.

     /cgi-bin/test.py?input=print%20"%20"%20"%20%20-+-\"


The python cgi script is simple:
     
    #!/usr/bin/python -w
    import cgi
    fs = cgi.FieldStorage()

    print "Content-type: text/plain\n"
    strE=fs.getvalue("input")
    print strE



my output is: 
     
     print " " "  - -\"


I don't understand why the '+' plus operator is substituted by space,
How may i pass the '+' plus operator?