class_docstr: Google Palm Vertexai LLM
  BaseGoogle class is extended for Google Palm model using Vertexai.
  The default model support at the moment is text-bison-001.
  However, user can choose to use code-bison-001 too.
docstr: Generates text for prompt.
  
  Args:
      prompt (str): A string representation of the prompt.
  
  Returns:
      str: LLM response.
code: def _generate_text(self, prompt: str) -> str:
      """
      Generates text for prompt.
  
      Args:
          prompt (str): A string representation of the prompt.
  
      Returns:
          str: LLM response.
  
      """
      self._validate()
  
      from vertexai.preview.language_models import (
          CodeGenerationModel,
          TextGenerationModel,
      )
      from vertexai.preview.generative_models import GenerativeModel
  
      if self.model in self._supported_code_models:
          code_generation = CodeGenerationModel.from_pretrained(
              self.model
          )
  
          completion = code_generation.predict(
              prefix=prompt,
              temperature=self.temperature,
              max_output_tokens=self.max_output_tokens,
          )
      elif self.model in self._supported_text_models:
          text_generation = TextGenerationModel.from_pretrained(
              self.model
          )
  
          completion = text_generation.predict(
              prompt=prompt,
              temperature=self.temperature,
              top_p=self.top_p,
              top_k=self.top_k,
              max_output_tokens=self.max_output_tokens,
          )
      elif self.model in self._supported_generative_models:
          model = GenerativeModel(self.model)
          responses = model.generate_content(
              [prompt],
              generation_config={
                  "max_output_tokens": self.max_output_tokens,
                  "temperature": self.temperature,
                  "top_p": self.top_p,
                  "top_k": self.top_k,
              },
          )
  
          completion = responses.candidates[0].content.parts[0]
      else:
          raise UnsupportedModelError(self.model)
  
      return completion.text
  
file_path: pandas-ai/pandasai/llm/google_vertexai.py
imports: from typing import Optional
  from .base import BaseGoogle
  from ..exceptions import UnsupportedModelError
  from ..helpers.optional import import_dependency
label_desc: Use image node_id 5 for calling the GoogleVertexAI obj's underlying member method code with example usage: obj._generate_text(prompt) and returns: completion