code: def violin(n=500,dispersion=3,categories=True,n_categories=5):
  		
  	df = histogram(1,n,dispersion,'abc')
  	df=df.rename(columns={'a':'data'})
  	if categories:
  		df['categories']=['category_{0}'.format(np.random.randint(n_categories)) for _ in range(n)]
  	return df
docs: Returns a DataFrame with the required format for 
  	a distribution plot (distplot)
  
  	Parameters:
  	-----------
  		n : int
  			Number of points 
  		categories : bool or int
  			If True, then a column with categories is added
  		n_categories : int
  			Number of categories