Fetch CO2 emission information (#3182)

* Fetch CO2 emission information

* fix blank lines

* fix blank lines

* Add type hints for function return values

* Update co2_emission.py

* Update co2_emission.py

* Update co2_emission.py

Co-authored-by: Christian Clauss <cclauss@me.com>

web_programming/co2_emission.py

@@ -0,0 +1,25 @@
+"""
+Get CO2 emission data from the UK CarbonIntensity API
+"""
+from datetime import date
+
+import requests
+
+BASE_URL = "https://api.carbonintensity.org.uk/intensity"
+
+
+# Emission in the last half hour
+def fetch_last_half_hour() -> str:
+    last_half_hour = requests.get(BASE_URL).json()["data"][0]
+    return last_half_hour["intensity"]["actual"]
+
+
+# Emissions in a specific date range
+def fetch_from_to(start, end) -> list:
+    return requests.get(f"{BASE_URL}/{start}/{end}").json()["data"]
+
+
+if __name__ == "__main__":
+    for entry in fetch_from_to(start=date(2020, 10, 1), end=date(2020, 10, 3)):
+        print("from {from} to {to}: {intensity[actual]}".format(**entry))
+    print(f"{fetch_last_half_hour() = }")