def _in_header(self, col):
if not self._has_header:<EOL><INDENT>icol_ex = pexdoc.exh.addex(RuntimeError, "<STR_LIT>")<EOL><DEDENT>hnf_ex = pexdoc.exh.addex(ValueError, "<STR_LIT>")<EOL>col_list = [col] if isinstance(col, (str, int)) else col<EOL>for item in col_list:<EOL><INDENT>edata = {"<STR_LIT>": "<STR_LIT>", "<STR_LIT:value>": item}<EOL>if not self._has_header:<EOL><INDENT>icol_ex(not isinstance(item, int))<EOL>hnf_ex((item < <NUM_LIT:0>) or (item > len(self._header) - <NUM_LIT:1>), edata)<EOL><DEDENT>else:<EOL><INDENT>hnf_ex(<EOL>(isinstance(item, int) and ((item < <NUM_LIT:0>) or (item > self._data_cols)))<EOL>or (<EOL>isinstance(item, str)<EOL>and (item.upper() not in self._header_upper)<EOL>),<EOL>edata,<EOL>)<EOL><DEDENT><DEDENT>return col_list<EOL>
Validate column identifier(s).