docs/basics.rst: Update validate_password() to take 3 arguments

This change updates the sample validate_password() function since it
actually receives 3 arguments when called, i.e. realm, username and
password.

Without this change, the following exception is raised:

    TypeError: validate_password() takes exactly 2 arguments (3 given)

1 files changed, 1 insertions, 1 deletions

diff --git a/docs/basics.rst b/docs/basics.rst
index 4b6ebd54..b1896f22 100644
--- a/docs/basics.rst
+++ b/docs/basics.rst
@@ -759,7 +759,7 @@ SSL or within a closed network.
 
    USERS = {'jon': 'secret'}
 
-   def validate_password(username, password):
+   def validate_password(realm, username, password):
        if username in USERS and USERS[username] == password:
           return True
        return False