remove unused function arguments

ezclimate/storage_tree.py

@@ -213,7 +213,7 @@ def write_columns(self, file_name, header, start_year=2015, delimiter=";"):
 			write_columns_csv(lst=[output_lst], file_name=file_name, header=["Year", "Node", header], 
 							  index=[years, nodes], delimiter=delimiter)
 
-	def write_columns_existing(self, file_name, header, delimiter=";"):
+	def write_columns_existing(self, file_name, header):
 		"""Save values in `tree` as columns into file  `file_name` in the 
 		'data' directory in the current working directory, when `file_name` already exists. 
 		If there is no 'data' directory, one is created. 

ezclimate/utility.py

@@ -322,7 +322,7 @@ def _mu_2(self, cons, prev_cons, ce_term):
 		     * prev_cons**self.r + self.b * ce_term)**((1.0/self.r)-1.0)
 		return t1 * t2
 
-	def _period_marginal_utility(self, prev_mu_0, prev_mu_1, m, period, utility_tree, cons_tree, ce_tree):
+	def _period_marginal_utility(self, period, utility_tree, cons_tree, ce_tree):
 		"""Marginal utility for each node in a period."""
 		damage_period = utility_tree.between_decision_times(period)
 		mu_0 = self._mu_0(cons_tree[period], ce_tree[period])