input: Write a function to eliminate lowercase sequences from a specified string.
  assert remove_lowercase("PYTHon") == 'PYTH'
  assert remove_lowercase("FInD") == 'FID'
  assert remove_lowercase("STRinG") == 'STRG'
output: def remove_lowercase(s):
      result = ''
      i = 0
      while i < len(s):
          if s[i].islower():
              while i < len(s) and s[i].islower():
                  i += 1
          else:
              result += s[i]
              i += 1
      return result