input: from typing import Dict
  
  def count_letter_positions(text: str) -> Dict[str, Dict[str, int]]:
      """ Given a string, count the positions where each letter occurs in the string.
      Return a dictionary where the keys are the letters and the values are dictionaries.
      The nested dictionaries have keys 'first', 'last', and 'count', representing 
      the first position of the letter, the last position of the letter, and the total 
      count of the letter in the string, respectively.
      >>> count_letter_positions("abracadabra")
      {'a': {'first': 0, 'last': 10, 'count': 5}, 'b': {'first': 1, 'last': 8, 'count': 2}, 
       'r': {'first': 2, 'last': 9, 'count': 2}, 'c': {'first': 4, 'last': 4, 'count': 1}, 
       'd': {'first': 6, 'last': 6, 'count': 1}}
      """
output:     result = {}
      for i, char in enumerate(text):
          if char not in result:
              result[char] = {'first': i, 'last': i, 'count': 1}
          else:
              result[char]['last'] = i
              result[char]['count'] += 1
      return result