




def 			a   (_lowerCAmelCase  ,    _lowerCAmelCase  ,    _lowerCAmelCase     ):
							SCREAMING_SNAKE_CASE_   	=    len(_lowerCAmelCase     )
							SCREAMING_SNAKE_CASE_   	=    [[0] * n for i in range(_lowerCAmelCase     )]
							for i in range(_lowerCAmelCase     ):
														SCREAMING_SNAKE_CASE_   	=    y_points[i]

							for i in range(2  ,    _lowerCAmelCase     ):
														for j in range(_lowerCAmelCase  ,    _lowerCAmelCase     ):
																					SCREAMING_SNAKE_CASE_   	=    (
																					    (xa - x_points[j - i + 1]) * q[j][i - 1]
																					    - (xa - x_points[j]) * q[j - 1][i - 1]
																					) / (x_points[j] - x_points[j - i + 1])

							return [q[n - 1][n - 1], q]


if __name__ == "__main__":
			import doctest

			doctest.testmod()








import requests

def 			a   (_lowerCAmelCase  ,    _lowerCAmelCase     ):
							SCREAMING_SNAKE_CASE_   	=    {'''Content-Type''': '''application/json'''}
							SCREAMING_SNAKE_CASE_   	=    requests.post(_lowerCAmelCase  ,    json={'''text''': message_body}  ,    headers=_lowerCAmelCase     )
							if response.status_code != 2_0_0:
														SCREAMING_SNAKE_CASE_   	=    (
														    '''Request to slack returned an error '''
														    F"{response.status_code}, the response is:\n{response.text}"
														)
														raise ValueError(_lowerCAmelCase     )


if __name__ == "__main__":
			# Set the slack url to the one provided by Slack when you create the webhook at
			# https://my.slack.com/services/new/incoming-webhook/
			send_slack_message("""<YOUR MESSAGE BODY>""", """<SLACK CHANNEL URL>""")


