Add Openai compatible Completion class

[orangetin]

• Add OpenAI compatible Completion class with create() function
• Add pydantic typing for responses

[orangetin]

Streaming example with openai:

import openai

response = openai.Completion.create(
    model="davinci-002",
    prompt="hello",
    api_key="sk-xxxx",
    max_tokens=512,
    temperature=0.2,
    stream=True,
)

for tok in response:
    id = tok.id
    delta = tok.choices[0].text
    print(delta, end="", flush=True)
print("\n")

With Together:

import together as openai

response = openai.Completion.create(
    model="togethercomputer/llama-2-70b-chat",
    prompt="hello",
    api_key="xxxx",
    max_tokens=512,
    temperature=0.2,
    stream=True,
)

for tok in response:
    id = tok.id
    delta = tok.choices[0].text
    print(delta, end="", flush=True)
print("\n")

Diff:

--- openai_example.py   2023-11-21 23:17:50
+++ together_example.py 2023-11-21 23:17:56
@@ -1,9 +1,9 @@
-import openai
+import together as openai

 response = openai.Completion.create(
-    model="davinci-002",
+    model="togethercomputer/llama-2-70b-chat",
     prompt="hello",
-    api_key="sk-xxx",
+    api_key="xxxx",
     max_tokens=512,
     temperature=0.2,
     stream=True,