def expand_tabs(file0):
 str_file_contents = open(file0, 'rb').read()
 str_pep_contents = str_file_contents.replace(' DCTB ', (4 * ' '))
 open(file0, 'wb').write(str_pep_contents)
 return None

def expand_tabs ( file0 ) : str_file_contents = open ( file0 , 'rb' ) . read ( ) str_pep_contents = str_file_contents . replace ( ' DCTB ' , ( 4 * ' ' ) ) open ( file0 , 'wb' ) . write ( str_pep_contents ) return None
this function takes the name of a python source file .