Filters a DataFrame for columns that contain the given strings. 
	Parameters:
	-----------
		include : bool
			If False then it will exclude items that match 
			the given filters.
			This is the same as passing a regex ^keyword
		kwargs : 
			Key value pairs that indicate the column and 
			value to screen for

	Example:
		df.screen(col1='string_to_match',col2=['string1','string2'])

def _screen(self,include=True,**kwargs):
	"""
	Filters a DataFrame for columns that contain the given strings. 
	Parameters:
	-----------
		include : bool
			If False then it will exclude items that match 
			the given filters.
			This is the same as passing a regex ^keyword
		kwargs : 
			Key value pairs that indicate the column and 
			value to screen for

	Example:
		df.screen(col1='string_to_match',col2=['string1','string2'])
	"""
	df=self.copy()
	for k,v in list(kwargs.items()):
		v=[v] if type(v)!=list else v
		if include:
			df=df[df[k].str.contains('|'.join(v),flags=re.IGNORECASE).fillna(False)]
		else:
			df=df[df[k].str.contains('|'.join(v),flags=re.IGNORECASE).fillna(False)==False]
	return df