[Tutor] local variable referenced before assignment

[ADRIAN KELLY]

hi all,keep getting the above error, can't understand or fix it, can anyone help.
def exchange():    euro=1    dollar=1.35    base=50    amount = input ('how much do you want to change')    if amount>base:        totalreturn=amount*dollar    else:        print 'not enough'    return totalreturn
print exchange() 

  

Adrian Kelly 
1 Bramble Close

Baylough

Athlone

County Westmeath

0879495663
 		 	   		  
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