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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_attr_value(self, attr_key, el_idx=0):
 """Return the value of the selected attribute in the selected element. Args: attr_key : str Name of attribute for which to search el_idx : int Index of element to use in the event that there are multiple sibling elements with the same name. Returns: str : Value of the selected attribute in the selected element. """

        return self.get_element_by_attr_key(attr_key, el_idx).attrib[attr_key]