Easy Language Error #1

Can anyone help me fix a code Bard provided to me that TS won’t accept? Error 1; Description: unknown identifier; Location: Camarilla; Line: 2

// Retrieve previous day’s high, low, and close prices
high_prev = GetPreviousDayHigh(Close, 1)
low_prev = GetPreviousDayLow(Close, 1)
close_prev = GetPreviousDayClose(Close, 1)

// Calculate the pivot point (PP)
PP = (high_prev + low_prev + close_prev) / 3

// Calculate support levels (S1, S2, S3, S4)
S1 = (PP - high_prev) + 2 * (PP - low_prev)
S2 = PP - 2 * (high_prev - low_prev)
S3 = PP - 3 * (high_prev - low_prev)
S4 = PP - 4 * (high_prev - low_prev)

// Calculate resistance levels (R1, R2, R3, R4)
R1 = (2 * PP) - low_prev
R2 = PP + (high_prev - low_prev)
R3 = PP + 2 * (high_prev - low_prev)
R4 = PP + 3 * (high_prev - low_prev)

// Plot the levels on the chart using appropriate EasyLanguage plotting functions
Plot(PP, “Pivot Point”, color.blue)
Plot(S1, “S1”, color.green)
Plot(S2, “S2”, color.green)
Plot(S3, “S3”, color.green)
Plot(S4, “S4”, color.green)
Plot(R1, “R1”, color.red)
Plot(R2, “R2”, color.red)
Plot(R3, “R3”, color.red)
Plot(R4, “R4”, color.red)