code: def get_tool_filepath(self, tool_alias):
          
          tools_dict = self.get_tools()
          if tool_alias in tools_dict:
              if self.tools_path is None:
                  return None
              else:
                  return os.path.join(self.tools_path, tool_alias)
          else:
              return None
docs: Given a visible tool alias, return the full path to the executable.
  
          Args:
              tool_alias (str): Tool alias to search for.
  
          Returns:
              (str): Filepath of executable, or None if the tool is not in the
                  suite. May also return None because this suite has not been saved
                  to disk, so a filepath hasn't yet been established.