code: def find_binary_in_path(filename):
      
      if 'PATH' not in os.environ:
          return None
      for directory in os.environ['PATH'].split(get_variable_separator()):
          binary = os.path.abspath(os.path.join(directory, filename))
          if os.path.isfile(binary) and os.access(binary, os.X_OK):
              return binary
      return None
docs: Searches for a binary named `filename` in the current PATH. If an executable is found, its absolute path is returned
      else None.
      :param filename: Filename of the binary
      :return: Absolute path or None