def angle2d(self):
if self.x==<NUM_LIT:0>:<EOL><INDENT>if   self.y<<NUM_LIT:0>:  return       math.pi/<NUM_LIT>*<NUM_LIT:3><EOL>elif self.y><NUM_LIT:0>:  return       math.pi/<NUM_LIT><EOL>else:           return <NUM_LIT:0><EOL><DEDENT>elif self.y==<NUM_LIT:0>:<EOL><INDENT>if   self.x<<NUM_LIT:0>:  return       math.pi<EOL>else:           return <NUM_LIT:0><EOL><DEDENT>ans = math.atan( self.y / self.x )<EOL>if self.x > <NUM_LIT:0>:<EOL><INDENT>if self.y><NUM_LIT:0>:    return ans<EOL>else:           return ans + math.pi*<NUM_LIT><EOL><DEDENT>else:               return ans + math.pi<EOL>
determine the angle of this point on a circle, measured in radians (presume values represent a Vector)