diff --git a/capa/features/extractors/vmray/call.py b/capa/features/extractors/vmray/call.py
index f6a3167a..8a247564 100644
--- a/capa/features/extractors/vmray/call.py
+++ b/capa/features/extractors/vmray/call.py
@@ -5,7 +5,7 @@ from capa.helpers import assert_never
 from capa.features.insn import API, Number
 from capa.features.common import String, Feature
 from capa.features.address import Address
-from capa.features.extractors.vmray.models import FunctionCall, Analysis
+from capa.features.extractors.vmray.models import Analysis, FunctionCall
 from capa.features.extractors.base_extractor import CallHandle, ThreadHandle, ProcessHandle
 
 logger = logging.getLogger(__name__)
@@ -18,12 +18,12 @@ def extract_function_calls(ph: ProcessHandle, th: ThreadHandle, ch: CallHandle)
 
     args:
       call: FunctionCall object representing the XML fncall element
-      
+
       yields: Feature, address; where Feature is either: API, Number, or String.
     """
 
     # Extract API name
-    yield API(ch.inner.name), ch.inner.address  
+    yield API(ch.inner.name), ch.inner.address
 
     # Extract arguments from <in>
     for param in ch.inner.in_:
@@ -49,9 +49,10 @@ def extract_function_calls(ph: ProcessHandle, th: ThreadHandle, ch: CallHandle)
         else:
             assert_never(value)
 
+
 def extract_features(analysis: Analysis) -> Iterator[Tuple[Feature, Address]]:
-    '''
+    """
     Extract features from the Analysis object in models.py
-    '''
+    """
     for fncall in analysis.fncalls:
-        yield from extract_function_calls(fncall)
\ No newline at end of file
+        yield from extract_function_calls(fncall)