def createBoundaries4Colorbar(df, step):
	"""
	Create list of boundaries for colorbar.

	:param pandas.DataFrame df: Data frame with 4 columns (sizes, labels, ranks, colors). Created by orsum_readResultFile() function.
	:param int step: Difference between each number in the sequence.

	:returs: **boundariesCB** (*list*) – list of values.
	"""
	boundariesCB = list(range(0, df['ranks'].max(), step))
	boundariesCB[0] = df['ranks'].min()
	if(df['ranks'].max() - boundariesCB[-1] < step/2):
		boundariesCB[-1] = df['ranks'].max()
	else:
		boundariesCB.append(df['ranks'].max())
	return(boundariesCB)