/in/foo.c:1:1: error: unknown type name 'def'
    1 | def calculate_BMI(height, weight):
      | ^~~
/in/foo.c: In function 'calculate_BMI':
/in/foo.c:1:34: error: expected declaration specifiers before ':' token
    1 | def calculate_BMI(height, weight):
      |                                  ^
/in/foo.c:1:5: warning: type of 'height' defaults to 'int' [-Wimplicit-int]
    1 | def calculate_BMI(height, weight):
      |     ^~~~~~~~~~~~~
/in/foo.c:1:5: warning: type of 'weight' defaults to 'int' [-Wimplicit-int]
/in/foo.c:18: warning: control reaches end of non-void function [-Wreturn-type]