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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 from_bytes(b):
 """ Extracts the r and s components from a byte string. Args: b (bytes):
 A 64-byte long string. The first 32 bytes are extracted as the r component and the second 32 bytes are extracted as the s component. Returns: Signature: A Signature object. Raises: ValueError: If signature is incorrect length """

        if len(b) != 64:
            raise ValueError("from_bytes: Signature length != 64.")
        r = int.from_bytes(b[0:32], 'big')
        s = int.from_bytes(b[32:64], 'big')
        return Signature(r, s)