Add comments to explain functions

Signed-off-by: Arianna Vespri <[email protected]>

Author: vesari

prometheus_client/openmetrics/parser.py

@@ -339,26 +339,42 @@ def _parse_nh_struct(text):
 
 
 def _compose_spans(span_matches, spans_name):
+    """Takes a list of span matches (expected to be a list of tuples) and a string 
+    (the expected span list name) and processes the list so that the values extracted 
+    from the span matches can be used to compose a tuple of BucketSpan objects"""
     spans = {}
     for match in span_matches:
+        # Extract the key from the match (first element of the tuple).
         key = match[0]
+        # Extract the value from the match (second element of the tuple).
+        # Split the value string by commas to get individual pairs, 
+        # split each pair by ':' to get start and end, and convert them to integers.
         value = [tuple(map(int, pair.split(':'))) for pair in match[1].split(',')]
+        # Store the processed value in the spans dictionary with the key.
         spans[key] = value
     if spans_name not in spans:
         return None
     out_spans = []
+    # Iterate over each start and end tuple in the list of tuples for the specified spans_name.
     for start, end in spans[spans_name]:
+        # Compose a BucketSpan object with the start and end values 
+        # and append it to the out_spans list.
         out_spans.append(BucketSpan(start, end))
+        # Convert to tuple
     out_spans_tuple = tuple(out_spans)
     return out_spans_tuple
 
 
 def _compose_deltas(deltas, deltas_name):
+    """Takes a list of deltas matches (a dictionary) and a string (the expected delta list name),
+    and processes its elements to compose a tuple of integers representing the deltas"""
     if deltas_name not in deltas:
         return None
     out_deltas = deltas.get(deltas_name)
     if out_deltas is not None and out_deltas.strip():
         elems = out_deltas.split(',')
+    # Convert each element in the list elems to an integer 
+    # after stripping whitespace and create a tuple from these integers.
     out_deltas_tuple = tuple(int(x.strip()) for x in elems)
     return out_deltas_tuple