Python_convert science notation

py_convert.py

def convert(num) :
    num = str(num)
    if ('e' in num):
        index = num.index('e')
        power = num[index+1::]
        power = int(power)
        num_num = num[:index]
        output = '0.' + '0'*(abs(power)-1) + num_num
        return (output)
    else :
        return (int(num))
      
a=0.00000000005
print (convert(a))  #0.00000000005 instead of 5e-11