Can't click on Angular component using selenium in python

What I want to do is to click on specific button/span/input written in Angular using Selenium in python. The propery of search is activated when span containing value of test search... is clicked. After typing the search phrase the combobox will show a list of related results.

Problem explanation with picture:

1.

2. 3. Select the first result and click it.

For this purpose I have implemented the following piece of code:

buy_container = driver.find_elements_by_xpath("//div[@class='instrument-search-box ng-isolate-scope']/button[@ng-click='titleClicked()']")
buy_container.click()
buy_container.send_keys('Mostafa')

AttributeError: 'list' object has no attribute 'click'

I have searched the whole source code for finding whether there is a class with the same type function of ng-click='titleClicked()' but I didn't find any!

Source Code

<div
  class="instrument-search-box ng-isolate-scope"
  focus-me="page.doSearch"
  show-btns="true"
  show-search="page.myList != 2"
  show-add-to-watch="page.myList == 1"
  select="getThisInstrument(instrument)"
  empty="emptyFirstInstrument()"
  add="marketWatch.addToWatch(instrument)"
  parent="theScope"
>
  <!-- ngIf: showWatchListCombo && $root.setting.closeRightBar && $root.changeLayout!==1 --><!-- ngIf: showWatchListCombo && $root.setting.closeRightBar && $root.changeLayout!==1 -->
  <div
    class="search-part searchable"
    ng-class="{'select-watch-list': showWatchListCombo &amp;&amp; $root.setting.closeRightBar &amp;&amp; $root.changeLayout!==1}"
  >
    <i
      class="question"
      ng-click="$root.showHelpModal('searchInstrument', $event)"
    ></i
    ><i class="Font Ico-search" ng-click="titleClicked()"></i>
    <div
      class="typeahead ng-isolate-scope ng-valid ng-hide ng-not-empty"
      ng-show="ins.doSearch"
      focus-me="focusMe"
      instrument-combo=""
      ng-model="ins.instrumentName"
      select="getInstrument(item)"
      empty="emptyInstrument()"
    >
      <input
        ng-disabled="ngDisabled"
        ng-model="ngModel"
        ng-change="query()"
        type="search"
        autocomplete="off"
        style="width: 100%;"
        placeholder="جستجوی نماد"
        class="ng-pristine ng-untouched ng-valid ng-not-empty"
        ng-show="ins.doSearch"
        focus-me="focusMe"
        instrument-combo=""
      /><!-- ngIf: isLoading -->
      <div class="combo" style="display: none;">
        <table class="table">
          <thead>
            <tr>
              <th>عنوان</th>
              <th>شرکت</th>
              <th>بازار</th>
            </tr>
          </thead>
          <tbody>
            <!-- ngRepeat: instrument in items -->
          </tbody>
        </table>
      </div>
    </div>
    <span
      ng-click="titleClicked()"
      ng-show="$root.selectedInstrument &amp;&amp; $root.selectedInstrument.Isin &amp;&amp; !ins.doSearch"
      title="با کلیک روی این قسمت امکان جستجوی نماد برای شما فراهم میگردد"
      class="ng-binding"
    >
      test search... </span
    ><!-- ngIf: (!$root.selectedInstrument || !$root.selectedInstrument.Isin) && !ins.doSearch -->
  </div>
  <div class="action">
    <!-- ngIf: showAddToWatch && ins.instrument && ins.instrument.Isin && $root.firstInstrument && ins.instrument.Isin == $root.firstInstrument.Isin --><!-- ngIf: showEmpty --><!-- ngIf: showBtns --><button
      class="btn-buy ng-scope"
      ng-if="showBtns"
      ng-click="$root.showOrderEntryModal('buy', 'SearchBar')"
    >
      خرید</button
    ><!-- end ngIf: showBtns --><!-- ngIf: showBtns --><button
      class="btn-Sell ng-scope"
      ng-if="showBtns"
      ng-click="$root.showOrderEntryModal('sell', 'SearchBar')"
    >
      فروش</button
    ><!-- end ngIf: showBtns -->
  </div>
  <!-- ngIf: !ins.doSearch && $root.selectedInstrument && $root.selectedInstrument.Isin && checkTime() --><!-- ngIf: !ins.doSearch && $root.selectedInstrument && $root.selectedInstrument.Isin && !checkTime() --><span
    title="قیمت پایانی"
    class="field ng-binding ng-scope green"
    ng-if="!ins.doSearch &amp;&amp; $root.selectedInstrument &amp;&amp; $root.selectedInstrument.Isin &amp;&amp; !checkTime()"
    ng-class="{green: $root.selectedInstrument.FinalPrice > 0, red: $root.selectedInstrument.FinalPrice < 0}"
    ><i class="question" ng-click="$root.showHelpModal('order', $event)"></i
    >
</div>

PS: I have also tried the following but faced with another error:

buy_container = WebDriverWait(driver, 5).until(EC.element_to_be_clickable((By.XPATH,"//div[@class='instrument-search-box ng-isolate-scope']/button[@ng-click='titleClicked()']")))
buy_container.click()

43 buy_container = WebDriverWait(driver, 5).until(EC.element_to_be_clickable((By.XPATH,"//div[@class='instrument-search-box ng-isolate-scope']/button[@ng-click='titleClicked()']")))
     44 buy_container.click()
     45 # buy_container.send_keys('Mostafa')

/home/mostafa/.local/lib/python3.6/site-packages/selenium/webdriver/support/wait.py in until(self, method, message)
     78             if time.time() > end_time:
     79                 break
---> 80         raise TimeoutException(message, screen, stacktrace)
     81 
     82     def until_not(self, method, message=''):
TimeoutException: Message:  

It doesn't have unique identifier or attribute like name, how can I solve this problem?