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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_sliced(self,slice,df=None):
 		""" 		Returns a sliced DataFrame 		Parameters 			slice : tuple(from,to) 				from : str 				to : str 					States the 'from' and 'to' values which 					will get rendered as df.ix[from:to] 			df : DataFrame 				If omitted then the QuantFigure.DataFrame is resampled. 		"""


		df=self.df.copy() if df==None else df
		if type(slice) not in (list,tuple):
			raise Exception('Slice must be a tuple two values')
		if len(slice)!=2:
			raise Exception('Slice must be a tuple two values')
		a,b=slice
		a=None if a in ('',None) else utils.make_string(a)
		b=None if b in ('',None) else utils.make_string(b)
		return df.ix[a:b]