code: def retrieve_function_string(functions, verbose=True):
      function_strings = ""
      if functions is None:
          return function_strings
      for function in functions:
          function_string = inspect.getsource(function)
          function_strings = function_strings + function_string + "\n"
      if verbose:
          print(">>> Functions")
          print(with_line_numbers(function_strings))
      return function_strings
  
imports: import inspect
  import os
  import re
  import sys
  import nbformat
  import numpy
  from hyperopt import fmin
  from nbconvert import PythonExporter
  from .ensemble import VotingModel
  from .utils import remove_imports, remove_all_comments, extract_imports, temp_string, write_temp_files, determine_indent, with_line_numbers, unpack_hyperopt_vals, eval_hyperopt_space, find_signature_end
label_desc: Use image node_id 8 for calling a global function with example usage: retrieve_function_string(functions, verbose) and returns: function_strings, function_strings