Add database_connection to example

* topics/maybe-monad.gmi: Add database_connection to example snippet.
Add missing ":" to example.

1 files changed, 7 insertions, 6 deletions

diff --git a/topics/maybe-monad.gmi b/topics/maybe-monad.gmi
index b748ad5..d6f87f2 100644
--- a/topics/maybe-monad.gmi
+++ b/topics/maybe-monad.gmi
@@ -37,15 +37,16 @@ foo.map(lambda x: 1 + x) \
 
 Finally, let's put all this together in a practical example using sql_query_mdict from genenetwork. Consider the following code using the DictCursor. The column foo may contain NULL values, and we need to check for them.
 ```
-with conn.cursor(MySQLdb.cursors.DictCursor) as cursor:
-    cursor.execute("SELECT foo FROM bar")
-    for row in cursor.fetchall():
-        if row["foo"] is not None:
-            print(row["foo"])
+with database_connection() as conn:
+    with conn.cursor(MySQLdb.cursors.DictCursor) as cursor:
+        cursor.execute("SELECT foo FROM bar")
+        for row in cursor.fetchall():
+            if row["foo"] is not None:
+                print(row["foo"])
 ```
 But, with sql_query_mdict, the row object is a MonadictDict where all values are monadic. We therefore do not need any special conditional checks.
 ```
-with database_connection() as conn
+with database_connection() as conn:
     for row in sql_query_mdict(conn, "SELECT foo FROM bar"):
         row["foo"].bind(print)
 ```