Odd strip behavior

[Rodrick Brown]

#!/usr/bin/python
 
def main():
 
    str1='this is a test'
    str2='t'
 
    print "".join([ c for c in str1 if c not in str2 ])
    print(str1.strip(str2))
 
if __name__ == '__main__':
    main()
 
./remove_str.py
his is a es
his is a tes

Why wasnt the t removed ?
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