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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 histogram(n_traces=1,n=500,dispersion=2,mode=None):
 	""" 	Returns a DataFrame with the required format for 	a histogram plot 	Parameters: 		n_traces : int 			Number of traces 		n : int 			Number of points for each trace 		mode : string 			Format for each item 				'abc' for alphabet columns 				'stocks' for random stock names 	"""
	
	df=pd.DataFrame(np.transpose([np.random.randn(n)+np.random.randint(-1*dispersion,dispersion) for _ in range(n_traces)]),
		columns=getName(n_traces,mode=mode))                     
	return df