code: def rm_file(self, iso_path, rr_name=None, joliet_path=None, udf_path=None):
          '''
          Remove a file from the ISO.
          Parameters:
           iso_path - The path to the file to remove.
           rr_name - The Rock Ridge name of the file to remove.
           joliet_path - The Joliet path to the file to remove.
           udf_path - The UDF path to the file to remove.
          Returns:
           Nothing.
          '''
          if not self._initialized:
              raise pycdlibexception.PyCdlibInvalidInput('This object is not yet initialized; call either open() or new() to create an ISO')
          iso_path_bytes = utils.normpath(iso_path)
          if not utils.starts_with_slash(iso_path_bytes):
              raise pycdlibexception.PyCdlibInvalidInput('Must be a path starting with /')
          child = self._find_iso_record(iso_path_bytes)
          if not child.is_file():
              raise pycdlibexception.PyCdlibInvalidInput('Cannot remove a directory with rm_file (try rm_directory instead)')
          if self.eltorito_boot_catalog is not None:
              if any([id(child) == id(rec) for rec in self.eltorito_boot_catalog.dirrecords]):
                  raise pycdlibexception.PyCdlibInvalidInput("Cannot remove a file that is referenced by El Torito; either use 'rm_eltorito' to remove El Torito first, or use 'rm_hard_link' to hide the entry")
              eltorito_entries = {}
              eltorito_entries[id(self.eltorito_boot_catalog.initial_entry.inode)] = True
              for sec in self.eltorito_boot_catalog.sections:
                  for entry in sec.section_entries:
                      eltorito_entries[id(entry.inode)] = True
              if id(child.inode) in eltorito_entries:
                  raise pycdlibexception.PyCdlibInvalidInput("Cannot remove a file that is referenced by El Torito; either use 'rm_eltorito' to remove El Torito first, or use 'rm_hard_link' to hide the entry")
          num_bytes_to_remove = 0
          udf_file_ident = None
          udf_file_entry = None
          if udf_path is not None:
              if self.udf_root is None:
                  raise pycdlibexception.PyCdlibInvalidInput('Can only specify a udf_path for a UDF ISO')
              udf_path_bytes = utils.normpath(udf_path)
              (udf_file_ident, udf_file_entry) = self._find_udf_record(udf_path_bytes)
          if child.inode is None:
              num_bytes_to_remove += self._remove_child_from_dr(child,
                                                                child.index_in_parent,
                                                                self.pvd.logical_block_size())
          else:
              while child.inode.linked_records:
                  rec = child.inode.linked_records[0]
                  if isinstance(rec, dr.DirectoryRecord):
                      num_bytes_to_remove += self._rm_dr_link(rec)
                  elif isinstance(rec, udfmod.UDFFileEntry):
                      num_bytes_to_remove += self._rm_udf_link(rec)
                  else:
                      raise pycdlibexception.PyCdlibInternalError('Saw a linked record that was neither ISO or UDF')
          if udf_file_ident is not None and udf_file_entry is None and udf_file_ident.parent is not None:
              self._rm_udf_file_ident(udf_file_ident.parent, udf_file_ident.fi)
              num_bytes_to_remove += self.pvd.logical_block_size()
          self._finish_remove(num_bytes_to_remove, True)