construct code, pre tags for sending email error logs

email_error.py

def error_msg(msg):
    styles = {
        'background': '#f4f4f4',
        'border': '1px solid #ddd',
        'border-left': '3px solid #f36d33',
        'color': '#666',
        'page-break-inside': 'avoid',
        'font-family': 'monospace',
        'font-size': '13px',
        'line-height': '1.6',
        'margin-bottom': '1.6em',
        'max-width': '100%',
        'overflow': 'auto',
        'padding': '1em 1.5em',
        'display': 'block',
        'word-wrap': 'break-word',
        'border-radius': '4px',
    }
    styles = ';'.join(['{}:{}'.format(x, styles[x]) for x in styles])
    return '<code><pre style="{}">{}</pre></code>'.format(styles, msg)