code: def get_elements(self, element, xmlns=None):
          
          real_element = ""
          real_xmlns = ""
  
          if xmlns is None:
              real_xmlns = "{" + self.xmlns + "}" if self.xmlns else ""
          else:
              real_xmlns = "{" + xmlns + "}"
  
          while "/" in element:
              l = element.split("/", 1)
              element = l[1]
              real_element += l[0] + "/"
              if element[0].isalpha() or element[0] == "_":
                  real_element += real_xmlns
  
          real_element += element
          return self.dom.findall(real_element)
docs: Return a list of elements those match the searching condition.
          If the XML input has namespaces, elements and attributes with prefixes
          in the form prefix:sometag get expanded to {namespace}element where the
          prefix is replaced by the full URI.  Also, if there is a default
          namespace, that full URI gets prepended to all of the non-prefixed tags.
          Element names can contain letters, digits, hyphens, underscores, and
          periods.  But element names must start with a letter or underscore.
          Here the while-clause is to set searching condition from
          `/element1/element2` to `/{namespace}element1/{namespace}/element2`
  
          Parameters:
              element: Searching condition to search certain elements in an XML
                       file. For more details about how to set searching
                       condition, refer to section `19.7.2.1. Example` and
                       `19.7.2.2. Supported XPath syntax` in
                       https://docs.python.org/2/library/xml.etree.elementtree.html
              xmlns:   XML namespace, default value to None.
                       None means that xmlns equals to the `self.xmlns` (default
                       namespace) instead of "" all the time.  Only string type
                       parameter (including "") will be regarded as a valid xml
                       namespace.
          Returns:
              (list): List of elements those match the searching condition