Click on a button using Selenium Python

I am trying to click on a button using Selenium Python which has the following HTML structure:

<div class="button c_button s_button" onclick="submitForm('mTF')">
    <input class="very_small" type="button"></input>
    <div class="s_image"></div>
    <span>
       Search
    </span>
</div>

<div class="button c_button s_button" onclick="submitForm('rMTF')" style="margin-bottom: 30px;">
    <input class="v_small" type="button"></input>
    <span>
          Reset
    </span>
I would like to be able to click both the Search and Reset buttons above (obviously individually).

I have tried a couple of things, for example:

driver.find_element_by_css_selector('.button .c_button .s_button').click() or,

driver.find_element_by_name('s_image').click() or,

driver.find_element_by_class_name('s_image').click() but, I seem to always end up with NoSuchElementException, for example:

selenium.common.exceptions.NoSuchElementException: Message: u'Unable to locate element: {"method":"name","selector":"s_image"}' ;

I wonder if I can somehow use the onclick() attributes of the HTML to make a Selenium click?

Any thoughts which can point me in the right direction would be great. Thanks.

For Python, use the

from selenium.webdriver import ActionChains

and

ActionChains(browser).click(element).perform()