docs: def add_volume(self,colorchange=True,column=None,name='',str='{name}',**kwargs):
  		"""
  		Add 'volume' study to QuantFigure.studies
  
  		Parameters:
  			colorchange : bool
  				If True then each volume bar will have a fill color 
  				depending on if 'base' had a positive or negative
  				change compared to the previous value
  				If False then each volume bar will have a fill color 
  				depending on if the volume data itself had a positive or negative
  				change compared to the previous value
  			column :string
  				Defines the data column name that contains the volume data. 
  				Default: 'volume'
  			name : string
  				Name given to the study
  			str : string
  				Label factory for studies
  				The following wildcards can be used:
  					{name} : Name of the column
  					{study} : Name of the study
  					{period} : Period used
  				Examples:
  					'study: {study} - period: {period}'
  			
  		kwargs : 
  			base : string
  				Defines the column which will define the
  				positive/negative changes (if colorchange=True).
  				Default = 'close'
  			up_color : string
  				Color for positive bars
  			down_color : string
  				Color for negative bars
  		"""
  		if not column:
  			column=self._d['volume']
  		up_color=kwargs.pop('up_color',self.theme['up_color'])
  		down_color=kwargs.pop('down_color',self.theme['down_color'])
  		study={'kind':'volume',
  			   'name':name,
  			   'params':{'colorchange':colorchange,'base':'close','column':column,
  						 'str':None},
  			  'display':utils.merge_dict({'up_color':up_color,'down_color':down_color},kwargs)}
  		self._add_study(study)