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# Python Collections - Set Math 2-nd Code Challenge Not Passing

"Couldnt find "covers" "-Error

sets.py
```COURSES = {
"Python Basics": {"Python", "functions", "variables",
"booleans", "integers", "floats",
"arrays", "strings", "exceptions",
"conditions", "input", "loops"},
"Java Basics": {"Java", "strings", "variables",
"input", "exceptions", "integers",
"booleans", "loops"},
"PHP Basics": {"PHP", "variables", "conditions",
"integers", "floats", "strings",
"booleans", "HTML"},
"Ruby Basics": {"Ruby", "strings", "floats",
"integers", "conditions",
"functions", "input"}
}
def covers(x):
a=[]
for key in COURSES:
if len(x&COURSES[key])>0:
a.append(key)
return a
def cover_all(x):
a=[]
for key in COURSES:
if len(x&COURSES[key])==len(x):
a.append(key)
return a
```

task: Great work! OK, let's create something a bit more refined. Create a new function named covers_all that takes a single set as an argument. Return the names of all of the courses, in a list, where all of the topics in the supplied set are covered. For example, covers_all({"conditions", "input"}) would return ["Python Basics", "Ruby Basics"]. Java Basics and PHP Basics would be exclude because they don't include both of those topics.

oh gosh... I found your problem. The function needs to be named "covers_all", not "cover_all".

The error "couldn't find covers" is odd because it's right there! Maybe it's because you need spaces before and after the function? Maybe it's because of the line

```if len(x&COURSES[key])>0
```

what are you trying to do with the '&'? I do not think you can do that with a str and a set. Maybe try

```if x in COURSES[key]:
```

instead? I'm just kind of guessing at what you're after. Please provide more detail if that doesn't help you out!

So when it said write a set as an argument I put my function as def covers_all({"strings", "input"}): The reason I used those words is because those keywords are in all courses of the list. Then I was gonna use the intersection function so it could call all the courses. Is that correct ? And how would I type that code out. Thats my biggest problem I dont know how to actually write the code out and how to write it out correctly. All advice welcomed

def cover_all(x): a=[] for key in COURSES: if len(x&COURSES[key])==len(x): a.append(key) return a