The AdvancedCalculator class represents many rows of calculators that support multiple expressions, as well as the use of variables. Lines will be separated by semicolons (;) and each token will be separated by a single space. Each line starts with the variable name, then the "=" character, and then a mathematical expression. The last line will also require a mathematical expression to be returned. You can assume that the expression will not refer to variables that have not yet been defined. You can assume that the variable names will be consistent and case sensitive. A valid variable name is a non-empty string of alphanumeric characters, the first of which must be a letter. You must use a "calculator" to evaluate each expression in this class, otherwise, no credit will be given.

class AdvancedCalculator: ''' >>> C = AdvancedCalculator() >>> C.states == {} True >>> C.setExpression('a = 5;b = 7 + a;a = 7;c = a + b;c = a * 0;return c') >>> C.calculateExpressions() == {'a = 5': {'a': 5.0}, 'b = 7 + a': {'a': 5.0, 'b': 12.0}, 'a = 7': {'a': 7.0, 'b': 12.0}, 'c = a + b': {'a': 7.0, 'b': 12.0, 'c': 19.0}, 'c = a * 0': {'a': 7.0, 'b': 12.0, 'c': 0.0}, '_return_': 0.0} True >>> C.states == {'a': 7.0, 'b': 12.0, 'c': 0.0} True >>> C.setExpression('x1 = 5;x2 = 7 * ( x1 - 1 );x1 = x2 - x1;return x2 + x1 ^ 3') >>> C.states == {} True >>> C.calculateExpressions() == {'x1 = 5': {'x1': 5.0}, 'x2 = 7 * ( x1 - 1 )': {'x1': 5.0, 'x2': 28.0}, 'x1 = x2 - x1': {'x1': 23.0, 'x2': 28.0}, '_return_': 12195.0} True >>> print(C.calculateExpressions()) {'x1 = 5': {'x1': 5.0}, 'x2 = 7 * ( x1 - 1 )': {'x1': 5.0, 'x2': 28.0}, 'x1 = x2 - x1': {'x1': 23.0, 'x2': 28.0}, '_return_': 12195.0} >>> C.states == {'x1': 23.0, 'x2': 28.0} True >>> C.setExpression('x1 = 5 * 5 + 97;x2 = 7 * ( x1 / 2 );x1 = x2 * 7 / x1;return x1 * ( x2 - 5 )') >>> C.calculateExpressions() == {'x1 = 5 * 5 + 97': {'x1': 122.0}, 'x2 = 7 * ( x1 / 2 )': {'x1': 122.0, 'x2': 427.0}, 'x1 = x2 * 7 / x1': {'x1': 24.5, 'x2': 427.0}, '_return_': 10339.0} True >>> C.states == {'x1': 24.5, 'x2': 427.0} True >>> C.setExpression('A = 1;B = A + 9;C = A + B;A = 20;D = A + B + C;return D - A') >>> C.calculateExpressions() == {'A = 1': {'A': 1.0}, 'B = A + 9': {'A': 1.0, 'B': 10.0}, 'C = A + B': {'A': 1.0, 'B': 10.0, 'C': 11.0}, 'A = 20': {'A': 20.0, 'B': 10.0, 'C': 11.0}, 'D = A + B + C': {'A': 20.0, 'B': 10.0, 'C': 11.0, 'D': 41.0}, '_return_': 21.0} True >>> C.states == {'A': 20.0, 'B': 10.0, 'C': 11.0, 'D': 41.0} True >>> C.setExpression('A = 1;B = A + 9;2C = A + B;A = 20;D = A + B + C;return D + A') >>> C.calculateExpressions() is None True >>> C.states == {} True ''' def __init__(self): self.expressions = '' self.states = {}

def setExpression(self, expression): self.expressions = expression self.states = {}

def _isVariable(self, word): ''' >>> C = AdvancedCalculator() >>> C._isVariable('volume') True >>> C._isVariable('4volume') False >>> C._isVariable('volume2') True >>> C._isVariable('vol%2') False ''' # YOUR CODE STARTS HERE pass

def _replaceVariables(self, expr): ''' >>> C = AdvancedCalculator() >>> C.states = {'x1': 23.0, 'x2': 28.0} >>> C._replaceVariables('1') '1' >>> C._replaceVariables('105 + x') >>> C._replaceVariables('7 * ( x1 - 1 )') '7 * ( 23.0 - 1 )' >>> C._replaceVariables('x2 - x1') '28.0 - 23.0' ''' # YOUR CODE STARTS HERE pass

def calculateExpressions(self): self.states = {} calcObj = Calculator() # method must use calcObj to compute each expression # YOUR CODE STARTS HERE pass

pls pls pls do it in your own way