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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 element_css_attribute_should_be(self, locator, prop, expected):
 		"""Verifies the element identified by `locator` has the expected 		value for the targeted `prop`. 		| *Argument* | *Description* | *Example* | 		| locator | Selenium 2 element locator | id=my_id | 		| prop | targeted css attribute | background-color | 		| expected | expected value | rgba(0, 128, 0, 1) |"""


		self._info("Verifying element '%s' has css attribute '%s' with a value of '%s'" % (locator, prop, expected))
		self._check_element_css_value(locator, prop, expected)