diff --git a/analyzer/__init__.py b/analyzer/__init__.py
index 9bec4e6..71f8bde 100644
--- a/analyzer/__init__.py
+++ b/analyzer/__init__.py
@@ -1,3 +1,4 @@
 from .analyzer import *
 from .biogames import *
 from .locomotion_action import *
+from .mask import *
diff --git a/analyzer/analyzer.py b/analyzer/analyzer.py
index dab3ad8..5f66b1e 100644
--- a/analyzer/analyzer.py
+++ b/analyzer/analyzer.py
@@ -40,7 +40,7 @@ class LocationAnalyzer(Analyzer):
 		raise NotImplementedError()
 
 	def process(self, entry: dict) -> bool:
-		if entry[self.settings.entry_type] in self.settings.spatials:
+		if entry[self.settings.type_field] in self.settings.spatials:
 			self.entries.append(entry)
 		return False
 
@@ -51,11 +51,11 @@ class LogEntryCountAnalyzer(Analyzer):
 	"""
 	__name__ = "LogEntryCount"
 
-	def result(self) -> defaultdict:
-		return self.store
+	def result(self) -> dict:
+		return dict(self.store)
 
 	def process(self, entry: dict) -> bool:
-		self.store[entry[self.settings.entry_type]] += 1
+		self.store[entry[self.settings.type_field]] += 1
 		return False
 
 	def __init__(self, settings: LogSettings):
@@ -73,7 +73,7 @@ class LogEntrySequenceAnalyzer(Analyzer):
 		return self.store
 
 	def process(self, entry: dict) -> bool:
-		entry_type = entry[self.settings.entry_type]
+		entry_type = entry[self.settings.type_field]
 		self.store.append(entry_type)
 		return False
 
@@ -89,7 +89,7 @@ class ActionSequenceAnalyzer(LogEntrySequenceAnalyzer):
 	__name__ = "ActionSequenceAnalyzer"
 
 	def process(self, entry: dict) -> bool:
-		entry_type = entry[self.settings.entry_type]
+		entry_type = entry[self.settings.type_field]
 		if entry_type in self.settings.spatials:
 			return False
 		self.store.append(entry_type)
diff --git a/analyzer/biogames.py b/analyzer/biogames.py
index e97a4e8..7c6d213 100644
--- a/analyzer/biogames.py
+++ b/analyzer/biogames.py
@@ -29,7 +29,7 @@ class BoardDurationAnalyzer(Analyzer):
 		return result
 
 	def process(self, entry: dict) -> bool:
-		entry_type = entry[self.settings.entry_type]
+		entry_type = entry[self.settings.type_field]
 		if entry_type in self.settings.boards:
 			self.store.append(self.save_entry(entry["board_id"], entry["timestamp"]))  # TODO: make configurable
 		return False
diff --git a/analyzer/locomotion_action.py b/analyzer/locomotion_action.py
index b2e3fab..f2dba97 100644
--- a/analyzer/locomotion_action.py
+++ b/analyzer/locomotion_action.py
@@ -9,14 +9,14 @@ from util import combinate
 def init_filter(settings: LogSettings, state: str) -> callable:
 	# this implies OR for lists; AND for dicts
 	if type(settings.sequences[state]) in (str, list):
-		return lambda entry: entry[settings.entry_type] in settings.sequences[state]
+		return lambda entry: entry[settings.type_field] in settings.sequences[state]
 	else:
 		return lambda entry: combinate(settings.sequences[state], entry)
 
 
-class LocomotionActionAnalyzer(Analyzer):  # TODO
+class LocomotionActionAnalyzer(Analyzer):
 	"""
-	calculate locomation/action times and ratio
+	calculate locomotion/action times and ratio
 
 	Anything between LogEntryCache and CacheEnableAction
 		is counted as ActionTime, the rest as LocomotionTime.
@@ -74,15 +74,16 @@ class LocomotionActionAnalyzer(Analyzer):  # TODO
 		self.last = None
 
 
-class CacheSequenceAnalyzer(Analyzer):  # TODO
+class CacheSequenceAnalyzer(Analyzer):
 	__name__ = "CacheSequence"
 
 	def process(self, entry: dict) -> bool:
 		if self.filter(entry):
 			if entry['cache']:
-				self.store.append((entry['timestamp'],entry['cache']['@id']))
+				self.store.append((entry['timestamp'], entry['cache']['@id']))
 			else:
-				self.store.append((entry['timestamp'],entry['cache']))
+				self.store.append((entry['timestamp'], entry['cache']))
+		return False
 
 	def result(self) -> list:
 		return self.store
diff --git a/analyzer/mask.py b/analyzer/mask.py
new file mode 100644
index 0000000..66038f1
--- /dev/null
+++ b/analyzer/mask.py
@@ -0,0 +1,15 @@
+from .analyzer import Analyzer
+
+
+class MaskSpatials(Analyzer):
+	__name__ = "MaskSpatials"
+	masked = 0
+
+	def process(self, entry: dict) -> bool:
+		if entry[self.settings.type_field] in self.settings.spatials:
+			self.masked += 1
+			return True
+		return False
+
+	def result(self) -> int:
+		return self.masked
\ No newline at end of file
diff --git a/log_analyzer.py b/log_analyzer.py
index cb26911..128af98 100644
--- a/log_analyzer.py
+++ b/log_analyzer.py
@@ -6,7 +6,7 @@ import analyzer
 
 class LogSettings:
 	log_format = None
-	entry_type = None
+	type_field = None
 	spatials = None
 	actions = None
 	analyzers = []
@@ -15,7 +15,7 @@ class LogSettings:
 
 	def __init__(self, json_dict):
 		self.log_format = json_dict['logFormat']
-		self.entry_type = json_dict['entryType']
+		self.type_field = json_dict['entryType']
 		self.spatials = json_dict['spatials']
 		self.actions = json_dict['actions']
 		self.boards = json_dict['boards']
@@ -27,7 +27,7 @@ class LogSettings:
 	def __repr__(self):
 		return str({
 			"logFormat": self.log_format,
-			"entryType": self.entry_type,
+			"entryType": self.type_field,
 			"spatials": self.spatials,
 			"actions": self.actions,
 			"analyzers": self.analyzers,
diff --git a/util/iter.py b/util/iter.py
index 9ad787a..3409b85 100644
--- a/util/iter.py
+++ b/util/iter.py
@@ -3,6 +3,8 @@ def json_path(obj: dict, key: str):
 	if not type(obj) is dict:
 		return None
 	if "." not in key:
+		if key not in obj:
+			return None
 		return obj[key]
 	child_key = key.split(".")
 	if child_key[0] not in obj:
@@ -10,9 +12,9 @@ def json_path(obj: dict, key: str):
 	return json_path(obj[child_key[0]], ".".join(child_key[1:]))
 
 
-def combinate(settings: dict, entry:dict)-> bool:
+def combinate(settings: dict, entry: dict) -> bool:
 	"""combine all settings {<key>: <expected>} with entry using AND"""
 	result = True
 	for key, value in settings.items():
 		result = result and json_path(entry, key) == value
-	return result
\ No newline at end of file
+	return result