returns column names from CTD download file

        :param str file_path: path to CTD download file

def get_column_names_from_file(file_path):
        """returns column names from CTD download file

        :param str file_path: path to CTD download file
        """
        if file_path.endswith('.gz'):
            file_handler = io.TextIOWrapper(io.BufferedReader(gzip.open(file_path)))
        else:
            file_handler = open(file_path, 'r')

        fields_line = False
        with file_handler as file:
            for line in file:
                line = line.strip()
                if not fields_line and re.search('#\s*Fields\s*:$', line):
                    fields_line = True
                elif fields_line and not (line == '' or line == '#'):
                    return [column.strip() for column in line[1:].split("\t")]