typo readme DSL example (#50)

s. import wasn't working for me, imported pprint

README.md

@@ -127,9 +127,11 @@ class UserDetails(BaseModel):
 ### Example 3: Using the DSL
 
 ```python
+from pprint import pprint
+
 from openai_function_call import OpenAISchema
 from openai_function_call.dsl import ChatCompletion, MultiTask, messages as m
-from openai_function_call.dsl.messages import system as s
+from openai_function_call.dsl.messages import SystemIdentity, SystemTask, SystemStyle, SystemGuidelines, SystemTips
 
 # Define a subtask you'd like to extract from then,
 # We'll use MultTask to easily map it to a List[Search]
@@ -140,15 +142,15 @@ class Search(OpenAISchema):
 
 tasks = (
     ChatCompletion(name="Acme Inc Email Segmentation", model="gpt-3.5-turbo-0613")
-    | s.Identity(identity="World class state of the art agent") # if no identity is provided, this is the default one
-    | s.Task(task="Segment emails into search queries")
-    | s.Style(style="Professional, clear and concise")
-    | s.Guidelines(guidelines=[
+    | SystemIdentity(identity="World class state of the art agent") # if no identity is provided, this is the default one
+    | SystemTask(task="Segment emails into search queries")
+    | SystemStyle(style="Professional, clear and concise")
+    | SystemGuidelines(guidelines=[
         'You never swear',
         'You are polite',
         'You say please and thank you often.'
     ])
-    | s.Tips(tips=[
+    | SystemTips(tips=[
         "When unsure about the correct segmentation, try to think about the task as a whole",
         "If acronyms are used expand them to their full form",
         "Use multiple phrases to describe the same thing"]