Skip headers where value is None, mimics requests, fix #132

curl_cffi/requests/headers.py

@@ -85,6 +85,7 @@ def __init__(
                     normalize_header_value(v, encoding),
                 )
                 for k, v in headers.items()
+                if v is not None
             ]
         else:
             if isinstance(headers[0], (str, bytes)):

tests/unittest/test_headers.py

@@ -0,0 +1,17 @@
+from curl_cffi.requests import Headers
+
+
+def test_headers():
+    headers = Headers()
+    headers['foo'] = 'bar'
+    headers['foo'] = 'baz'
+    assert headers['foo'] == 'baz'
+    assert headers.get('foo') == 'baz'
+    assert headers.get('bar') is None
+    assert headers
+
+
+def test_headers_none_value():
+    headers = Headers({"foo": None, "bar": ""})
+    assert headers.get("foo") is None
+    assert headers["bar"] == ""